Thesis
Reference
Demographic, psychosocial, health and personality predictors of depression and quality of life: importance of an integrative framework
WEBER, Kerstin Maud
Abstract
L'étude transversale investigue l'influence des cinq dimensions de personnalité (selon Costa
& McCrae, 1992) sur le lien entre dépression majeure et qualité de vie. Adoptant une approche intégrative, elle compare 79 patients ambulatoires et 102 sujets non-dépressifs, en tenant compte de covariées démographiques, psychosociales, et de leur santé physique.
Trois dimensions de personnalité, à savoir l'Ouverture à l'expérience, la Conscience et le Névrosisme influencent directement la qualité de vie après avoir contrôlé pour la sévérité de la dépression. De plus, le Névrosisme et la Conscience augmentent indirectement la qualité de vie en modérant l'effet de la dépression sur celle-ci. Un accent particulier est mis sur la dépression dans deux groupes d'âge. La qualité de vie des adultes jeunes est déterminée uniquement par la sévérité de la dépression, alors que celle des adultes âgés est de nature multi-déterminée : sévérité symptômes, risque suicidaire, comorbidités physiques et dimensions de personnalité.
WEBER, Kerstin Maud. Demographic, psychosocial, health and personality predictors of depression and quality of life: importance of an integrative framework. Thèse de doctorat : Univ. Genève, 2012, no. FPSE 509
URN : urn:nbn:ch:unige-242087
DOI : 10.13097/archive-ouverte/unige:24208
Available at:
http://archive-ouverte.unige.ch/unige:24208
Disclaimer: layout of this document may differ from the published version.
Section de Psychologie
Sous la direction de Professeur Anik de Ribaupierre
DEMOGRAPHIC, PSYCHOSOCIAL, HEALTH AND PERSONALITY PREDICTORS OF DEPRESSION AND QUALITY OF LIFE:
IMPORTANCE OF AN INTEGRATIVE FRAMEWORK
THESE
Présentée à la
Faculté de psychologie et des sciences de l’éducation de l’Université de Genève
pour obtenir le grade de Docteur en Psychologie
Kerstin WEBER
Luxembourg Thèse No 509
GENEVE 2012
Objective: The present study investigated the relationship between the five main personality dimensions defined by Costa and McCrae (1992) - namely Neuroticism, Extraversion, Openness to experience, Agreeability, and Conscientiousness - and depressive mood in both young and old age depressed outpatients, in comparison to healthy controls. In addition, the study assessed the moderating impact of these personality dimensions on the relationship between depression and participants’ subjective quality of life. Following an integrative approach, the relationships between personality and depression, respectively quality of life, were assessed after taking into account the influence of demographic, psychosocial and physical health covariates, whose influence on depression had been reported in the literature.
Methods: The study design included a cross-sectional comparison between 79 outpatients with DSM-IV nonpsychotic major depression and 102 healthy controls as selected by means of the Mini International Neuropsychiatric Interview, and divided into young (mean age = 35 years) and old adults (mean age = 70 years). Personality was assessed with the NEO Personality Inventory, while study psychologists rated depression on the Hamilton Rating Scale for Depression (HRSD), and participants self-rated their subjective quality of life with the World Health Organization Quality of Life - Bref (WHOQOL-Bref). Covariates included demographic variables (age, gender, level of education), psychosocial characteristics (marital status, social support, functional dependency, stressful life events), as well as physical health status (Cumulative Illness Rating Scale, CIRS).
Results: First, Neuroticism was the only personality dimension that positively predicted depressive symptoms (R2=0.16), once the significant influences of age, comorbid physical diseases and negative subjective emotional impact of stressful life events had been accounted for (R2=0.49). Second, interestingly, this pattern differed, when the influence of personality was analysed on the relationship between depression and quality of life. In addition to high Neuroticism, which lowered quality of life, Openness to experience and Conscientiousness showed a direct protective influence, while Neuroticism and Conscientiousness enhanced patients’ quality of life by interacting with depression. 67% of the quality of life variance was explained by the depressive symptoms, while these four personality dimensions explained an additional 5%, after accounting for the protecting influence of female gender. Third, with respect to specific age-related differences in predictor
differences in quality of life, in young age, high quality of life was solely predicted by low severity of depressive mood. In contrast, in old age, high quality of life was best predicted by a more complex model including low depressive symptom severity and low suicide risk, together with low levels of physical comorbidity, and high levels of Openness to experience and Agreeableness dimensions of personality. Plus, Openness and Conscientiousness interacted with depression to lower its influence on quality of life in the old age group.
Conclusion: Evidence showed the benefits of an integrative approach. Overall, results suggested that major depression is a multifactorial disorder, influenced by a series of both risk and protective factors, including age, level Neuroticism, physical comorbidities and impact of stressful life events. The relative importance of these factors was dependent on patients’ age. Indeed, young versus old age depression was best distinguished by the severity of symptoms, both depressive and somatic. Neuroticism and life stressors did not significantly distinguish younger from older depressed patients. Regarding quality of life, the influence of personality was not limited to Neuroticism, but depended also on Openness to experience and Conscientiousness, directly or via their impact on depressive symptoms.
Again, the importance of predictors depended on participants’ age. While symptom severity dominated the level of quality of life in younger age, the influences on quality of life in old age were more complex in nature, including depression features, physical health and personality dimensions, such as Agreeableness in addition to Openness and Conscientiousness.
Table of content
Pages
Acknowledgements 1
Introduction 3
Personality, depression and quality of life: literature review Five-Factor Theory
Five-Factor Theory and aging
Five-Factor Theory in clinical samples
Personality and depression Longitudinal evidence Cross-sectional evidence
Personality, depression and quality of life
Integrative approach
Integrative approaches in young age Integrative approaches in old age
One step beyond the current state of the art
7
9 10 12
12 13 15
17
21 21 24
26
Thesis objectives Hypotheses
30
32
Methods
Study design Age groups
Participant selection Recruitment procedure Assessment tools Sample characteristics Statistical analyses
34
34 35 36 37 38 40 44
Quality of life
Five factors of personality Correlation matrix
Objective I: predictors of depression Objective II: predictors of quality of life Objective III: age specificities in predictors
48 49 50
51 56 58
Discussion
Depression and quality of life outcomes Objective I: predictors of depression Objective II: predictors of quality of life Objective III: age specificities in predictors
Strengths and weaknesses
62
63 64 72 77
80
Conclusions 81
References 84
Résumé en langue française 95
Appendix
Appendix 1: NEO PI-R
Appendix 2: Informed consent Appendix 3: SRRS
Appendix 4: Details on additional data Appendix 5: Reviewers’ comments
Appendix 6: Latest versions of the three articles 6a: Aging & Mental Health
6b: Psychogeriatrics (submitted)
6c: Journal of Geriatric Psychiatry and Neurology (submitted)
124
ACKNOWLEDGMENTS
It takes a long time to finish a PhD thesis. It takes even more time if one writes a second project with a new topic after 3 years; because one’s professional and personal life has moved on to new horizons. Therefore, I really wish to express my thanks to the people who never stopped encouraging my work and who have supported this adventure and cared for my project, even during its second run.
I am sincerely grateful to my supervisor and director, Professor Anik de Ribaupierre. Our encounter between a life-long university teacher, researcher with a passion for details and a young impatient, full-time working clinician was a real challenge. She would repeatedly comment on my rather straightforward writing style by adding in the margin “vous n’avez pas vraiment démontré ceci…”, “vous allez un peu trop loin…”, and very patiently add the essential subtle differences and accuracies, when I was prematurely jumping to conclusions.
I would sincerely like to thank her for trusting me, and for teaching me her outstanding rigour in a very gentle, yet firm way.
The composition of the jury members of my thesis turned out to be a very rewarding challenge. Christophe Delaloye taught me how to question my empirical findings, and make sure my thesis was guided by scientific criticism rather than clinical experience and background. With his astonishing capacity to make coefficients and tests sound like natural and obvious mind games, Paolo Ghisletta gave me the courage to strengthen my statistical knowledge offering very clear and pragmatic references. Panteleimon Giannakopoulos always reminded me of the possible clinical implications and applications of the study, and allowed me to look further than the scope of the thesis. Simultaneously, Thierry Lecerf questioned my reasoning and clinical perspectives with relevant and refreshing alternatives, helping me to reframe the thesis in the context of normal personality development. I would also like to thank Professor Urs Mosimann, who accepted to be part of the jury as an external member.
Next, I owe my sincere gratitude to Professor Panteleimon Giannakopoulos, who offered me the opportunity to make the thesis come true, while I was working full-time in the psychiatry and mental health department, as part of my function as a psychologist in the hospital.
Always willing to correct my articles with an impressive speed, he has never given up on any of the manuscripts once they had been started. He has taught me how to sort out and prioritize my ideas, and try to avoid suffocating them with a avalanche of information. Not to forget Alessandra Canuto, my irreplaceable guide, when it comes to defend SNSF research proposals on the issue of personality in a record amount of time. I am very fortunate that she made me discover the NEO PI-R, a precious tool that hasn’t left my daily practice since I first used it 10 years ago. Never giving up on human mankind, she has taught me to always carefully look for the individual with its essential character and soul, no matter how well these are hidden behind disturbing or fascinating psychopathological symptoms.
This PhD thesis was meant to be part of two larger funded research projects. Their team would not have been complete without François R. Herrmann, whose never-ending optimism and humour really helped me to become friends with methodology and research. One of
these projects remains unsupported until today and thus the longitudinal extension of the thesis will not take place. I am grateful for having these wise research companions, who taught me how to bare this frustration with the necessary distance.
Without data, a PhD thesis becomes impossible. Many people helped me with data collection, for which I would like to thank them wholeheartedly. 205 patients and controls have filled out questionnaires for me. Without their generosity, this study would never have been possible. Without the spontaneous help from my psychiatry colleagues, none of the 91 patients would have known about the existence of the study, and I would like to thank them:
Jean-Pierre Bacchetta, Javier Bartolomei, Sergio DiGiorgio, Andri Meiler, Corina Meiler, Nadia Ortiz, and Stéphanie Quast. Most importantly, I wish to express my thanks to Aline Mouchian, and her precious help with conducting some of the 205 interviews and entering the data in the 181 x 240 = 43.440 excel cells on personality. Besides, it was refreshing to also share the funny anecdotes and misfortunes in fighting for available offices and room keys to conduct our interviews in five different HUG sites.
I am very fortunate to have an understanding and generous husband. He and my daughter deserve special thanks for their ever-present support and the way they managed to deal with my lack of sleep, moments of frustration and my own rather stubborn personality. Having a picnic in the mountains and smiling at my daughter’s songs was sometimes all I needed after spending a long evening fighting with data. And without my husband’s gift of a brand- new laptop, I would not have been able to carry my thesis around with me wherever I went for the last 3 years. Special thanks also to my friends and colleagues, who listened to me in difficult moments and who shared my enthusiasm in the good moments. My warmest thanks to my parents-in-law, who never refused to help out with babysitting and cooking, when I was too busy getting lost in books and articles. Humble thanks to my mother, who made me become a psychologist and psychotherapist in the first place, by introducing me to this rewarding and demanding profession. And finally, very sincere thanks to my father and to my brother for being such inspiring examples and helping me to develop my curiosity. They gave me faith in finding my own way along this very special adventure.
This work on the personality traits of 181 other adults offered a unique opportunity to become aware of and reshape my own character. Thank you for sharing the journey.
Demographic, psychosocial, health and personality predictors of depression and quality of life: importance of an integrative framework
INTRODUCTION
In the daily clinical routine of psychiatric institutions in western countries, personality disorders (or traits) are identified using categorical approaches (Millon, 2012), such as the International Classification of Disease (CIM-10) developed by the World Health Organization. Recently the dimensional approach of personality such as the Five-Factor Theory has gained in interest especially in old age populations (Agronin & Maletta, 2000), and has been widely used in the psychogeriatric units of the Department of Mental Health and Psychiatry in Geneva (Canuto et al., 2008; 2009). Traits models of personality, such as the Big Five (John et al., 2008) or the Five-Factor Theory (McCrae & Costa, 2008), have been adopted as consensual frameworks to determine each person’s individuality as a function of five broad dimensions; Neuroticism, Extraversion, Openness to experience, Agreeableness and Conscientiousness. According to these models, personality traits are pervasive and enduring patterns of thoughts, feelings and behaviours, which are formed through childhood and increase in consistency throughout the lifespan with a peak after age 50 in the general population (Roberts & DelVecchio, 2000; Bazana & Stelmack, 2004). The normative mean-level changes show that individuals become more mature, socially dominant, agreeable, conscientious, and emotionally stable over time (Roberts et al., 2006).
In respect to psychiatric samples, mood disorders such as major depression have been usually related to categorical personality disorders rather than personality dimensions (Widiger & Smith, 2008). A variety of models of the relationship between depression and personality have been described in younger patients (Klein et al, 2011; Widiger & Smith, 2008). They can be grouped into three approaches synthesized by Klein et al. (2011).
Precursor models exclude a causal relationship between these two variables. They consider that personality disorders represent an early manifestation of depression and that both depression and personality may share a common aetiology. Predisposition models posit that personality plays a causal role in the onset of depression. Pathoplasticity models similarly consider that personality has a direct yet not causal relationship with depression. Instead of determining its onset, personality influences the expression of depression after onset, namely the severity of the symptoms, their course and their response to treatment. To date, the evidence supporting the association between depressive disorders and personality
dimensions in later life periods remains scarce (Weber et al., 2011). However, in my daily clinical practice, as well as in a previous study on depression and personality in old age (Canuto et al., 2009), the pathoplasticity model appears to be the most appealing. In this study, personality explained the variations in the clinical presentation or outcome among depressed individuals.
Moreover, the severity of depressive symptoms is not the only significant outcome to consider in patients with recurrent depression. Recently, subjective quality of life has emerged as a promising outcome variable to assess patients’ well-being in relationship to their depressive mood in young (Pyne et al., 1997) and old age (Chan et al., 2006;
Doraiswamy, 2002; Naumann & Byrne, 2004). However, none of those studies has addressed age-related differences in the personality-quality of life relationship in depressed patients. In fact, most studies that compared age differences in relation to quality of life focused on non-clinical samples without depression (Mroczek & Spiro, 2003). To address this issue, in the present study, the relationships between personality and depression respectively quality of life were analysed, after accounting for confounding variables that are classically known to influence depression and well-being. In agreement with a bio-psycho- social approach in depression (e.g. Kendler et al., 1993; 2002), demographic risk factors such as female gender are interacting with psychosocial risks such as the loss of independency and stressful life events, health variables such as comorbid physical illnesses, and individual patient characteristics such as the five personality dimensions, to determine the clinical evolution of depression. As Carol D. Ryff recommended, and as I share as a clinician trained in a systemic approach with ten years of clinical experience in geriatric psychiatry, the goal is “to go for the whole story despite the inevitable complexities involved […] and put the separate pieces together in order to describe the whole people and the multiple forces, internal and external” (2008, p. 412) that affect personality, old age, depression and well-being. Therefore, the goal of the present project was to explore the links between domains that have so far been considered as separate entities by the vast majority of the existing studies, as displayed below in Figure 1.
The adopted theoretical framework was that of the pathoplastic model. Personality was expected to influence the presence and severity of depressive symptoms (full line in Figure 1), as well as the impact of depression on patients’ subjective quality of life (dotted line).
Obviously, testing the pathoplastic versus predisposition model would request a longitudinal study design evaluating personality dimensions, clinical features, and depression course over time in order to test whether personality predicts depression outcome after controlling for the other variables. However, the timeframe and resources of the PhD thesis called for a
cross-sectional comparison. Instead of assessing personality and depression over the course of the disorder (i.e. during and after a depressive episode), their relationship was assessed in depressed patients in comparison to never-depressed healthy controls. To address age-related differences in this relationship, the thesis included young as well as old age participants. Regarding the integrative approach, the context of the present study did not allow for recruitment of a sample large enough for a comprehensive statistical model exclusively including all predictive variables. Instead, three separate articles were submitted for publication and each successively focused specifically on one of the aspects of the project. The present PhD thesis proposes an overview of the entire project and explains the rationale of each article.
Figure 1: Theoretical framework
A first objective focused on the relationship between the big five personality dimensions (as defined by the Five-Factor Theory) and episodes of major depression, after accounting for other independent predictors such as socio-demographics, physical comorbidities and stressful life events. Following the rationale of the pathoplastic model, depression was assessed not only as a categorical DSM-IV-R diagnosis (case-control), but also on a dimensional depressive symptoms severity scale. This allowed for taking into account the age-related differences in the clinical presentation of depression, such as the milder nature of symptoms in old age (Meeks et al., 2011). The first article published in Aging and Mental Health (Appendix 6a) focused on the prediction of depression by age, education, physical illness, level of functional dependency (as defined by the hours of professional home care),
5 personality dimensions
• Neuroticism
• Extraversion
• Openness to experience
• Agreeableness
• Conscientiousness
Major depression Subjective
quality of life Demographics (i.e. age)
Psychosocial variables (i.e. life stress) Physical comorbidities
as well as the five personality dimensions. This article, as well as the additional results presented in the thesis, documented that depression is best predicted by age, the impact of stressful life events, physical illness and Neuroticism. None of the remaining personality dimensions were significant predictors of depression. Given the importance of stressful life events in the prediction of depression revealed by the literature review and confirmed by the results of this first work, the second article (Appendix 6b), submitted for publication in the Psychogeriatrics, specifically discussed the relationship between life stressors, personality and depression. Importantly, the findings of this additional work indicated that the subjective emotional impact rather than the amount of a priori stressful life events is significantly related to major depression.
A second objective focused on the investigation of the association between subjective quality of life and personality dimensions in depressed and non-depressed participants.
Indeed, depressed patient’s perception of their well-being determines their utilization of health services and satisfaction with treatment (Hunt & McKenna, 1992; Stedman, 1996).
Not surprisingly, this variable gains increasing interest in health care studies (Böckerman et al., 2011). As mentioned, most studies on depression and quality of life did not include personality, and those focusing on quality of life and personality were largely conducted in healthy samples. There is an emerging interest in simultaneously addressing quality of life, personality and aging (Ryff, 2008) and the present study attempted to address this issue in never-depressed controls as well as in depressed outpatients by means of a generic health- related quality of life measure. The third PhD article, submitted to Journal of Geriatric Psychiatry and Neurology (Appendix 6c) focused on the relationship between personality, depression and quality of life while taking into account psychosocial and physical health variables. As presented in this thesis, results of the regression model showed that quality of life is best predicted by depression severity, gender, Neuroticism, Openness to experience and Conscientiousness. While the mood symptoms and Neuroticism emerged as risk factors, female gender, Openness and Conscientiousness enhanced the level of quality of life. Neuroticism and Conscientiousness interacted with depression to moderate its influence on quality of life.
This thesis work also provided some relevant observations in respect to the determinants of depression across the life spectrum. A first regression model predicting depression in old age (as opposed to young age), confirmed that this variable was associated with lower severity of symptoms and higher intensity of physical illness. Neither the impact of stressful life events nor Neuroticism emerged as significant predictors. Regarding quality of life, in young age, this outcome is predicted solely by the severity of depressive symptoms. In
contrast, in old age, higher quality of life is directly associated with higher levels of Openness to experience and Agreeableness dimensions. Further, Openness and Conscientiousness are interacting with depression to lower its impact on quality of life. In this age group, lower quality of life is predicted by severity of depressive symptoms, suicide risk and physical illness.
After a synthesis of this current state of the art, the three objectives and the research method will be detailed. Results are presented in response to the objectives and followed by critical discussion of the findings and a conclusion on treatment implications and future perspectives.
PERSONALITY, DEPRESSION AND QUALITY OF LIFE: LITERATURE REVIEW
As Widiger and Smith (2008) reminded, the importance of personality to psychopathology has been recognized since the beginning of medicine, with the four distinct humours of Hippocratic medicine corresponding to the four temperaments, which evolve in balance when a person is healthy. Imbalances - caused by excesses or deficits of these humours - were thought to increase the vulnerability for diseases and disorders.
Traditionally, personality in medicine is most frequently addressed in terms of personality disorders, as described by the Diagnostic and Statistical Manual of Mental Disorders (DSM- IV-TR) and considered via a categorical approach (Millon, 2012). In psychology, personality is measured as a non-pathological concept that characterizes the healthy development of each person, and allows for describing individual differences in the human nature. It is defined as a dynamic and organized set of characteristics of each individual, that uniquely influences his or her cognitions, emotions, motivations, and behaviours in various situations (John et al., 2008). Personality psychology has a rich history and abundance of theoretical traditions, including psychodynamic, humanistic, biological, behaviourist and social perspectives, as well as the dispositional trait perspective, which will be used in this project (John et al., 2008). To date, there are numerous lines of evidence supporting the idea that the categorical DSM-IV-TR diagnosis of personality disorders are maladaptive variants of the general personality structure (Clark, 2005; Lynam & Widiger, 2001; Widiger & Lowe, 2007). Personality disorders are conceptualized as extreme, and therefore, dysfunctional variants of traits that are present in each individual (Bagby et al., 1999; Mullins-Sweatt &
Widiger, 2009; Widiger & Simonsen, 2005). Cloninger and his team have developed a
research work defining personality disorders as maladaptive syndromes developed through person-environment interaction. These authors conceptualize personality disorders as a failure of integrative functions of personality caused by biogenetic dispositions and/or pathological contextual effects (Svrakic & Cloninger, 2010). Widiger and Lowe (2007) have proposed a four-step procedure for clinicians to diagnose a personality disorder consistent with the tendency of the future DSM-V towards a dimensional approach of personality. The potential integration of normal personality traits and personality disorders represents an important paradigm shift from a the normal/abnormal boundary approach to a continuum, raising complex and passionate debates as reflected by the latest contributions of Widiger (2011). This dimensional assessment of personality has been shown to be statistically more powerful than the categorical diagnosis of personality disorders in predicting depression outcome in interpersonal psychotherapy (Joyce et al., 2007).
Most of the existing studies on personality domains, their genetic and contextual determinants, and the relationship of personality and depression, were performed in young and middle aged adults. Only a few studies have focused on personality disorders and dimensions in later life leading to controversial conclusions. Some of them suggested that the use of a dimensional approach provides a more reliable diagnosis of personality function over time compared to the traditional categorical approach (for review see Agronin &
Maletta, 2000). Other authors postulated that a dimensional approach might improve medical treatment decisions and clinical communications, but empirical prevalence studies would continue to encounter the same difficulties with over- and underestimations of the prevalence of personality disorders (Balsis et al., 2009). Whether authors consider personality traits or disorders, interplay of personality and psychopathology forms a clinically and empirically significant and challenging debate. While personality assessment may be routinely part of clinical evaluations, systematic research on the impact of personality traits on antidepressant treatment selection, compliance and outcome, is remarkably sparse in old age (Weber et al., 2011). Since 2005, about 10 studies focused on the impact of personality on depression outcome. Interestingly, since 2010, a few articles started to address the multi- facet nature of late-life depression by studying cognitive, structural imaging and psychological vulnerability markers.
Five-Factor Theory
In psychology, five big personality dimensions were identified by a lexical approach having their origins in the natural language of description of personality traits (John et al., 2008). In his review, John et al. describes how in the years 1930, the basic assumption guiding the pioneer work of psychologists was the idea that most socially relevant and salient personality characteristics are encoded in the natural language. Researchers such as Allport and Odbert classified these terms into prototypical categories; and Cattell and collaborators provided the first clustering of major dimensions of personality. After fifty years of very fruitful researches, five main dimensions emerged as recurrent and solid factors, replicated by different authors, frequently known as the Big Five, to reflect their very broad and higher- order level of classification (John et al., 2008).
The Five-Factor Theory of personality by Costa and McCrae (1992) offers an integrative framework of these five broad dimensions. This trait model categorizes relatively enduring and recurrent patterns of thoughts, feelings and behaviours, which simultaneously characterize and differentiate individuals. It defines basic tendencies that are internal psychological realities, and characteristic adaptations describing their concrete manifestations in the personality system. According to the authors, the deeper psychological entities are not accessible to direct observation, yet can be inferred from self-rated questionnaires (McCrae & John, 2008). Costa and McCrae originally developed a standardized three-dimensional personality measure of Neuroticism, Extraversion and Openness to experience in 1985, before adding Agreeableness and Conscientiousness in 1992, to create a five-factor inventory, known as the 240-item NEO Personality Inventory – Revised (NEO PI-R). Neuroticism contrasts emotional stability and even-temperedness with negative emotionality, such as feeling anxious, nervous, sad or tense. Extraversion implies an energetic approach towards the social and material world and includes traits such as sociability, activity, assertiveness, and positive emotionality. Openness to experience versus closed-mindedness describes the breadth, depth, originality, and complexity of the person’s mental and experiential life. Agreeableness contrasts a prosocial and communal orientation towards others with antagonism and includes traits such as altruism, tender-mindedness, trust and modesty. Finally, Conscientiousness describes socially prescribed impulse control that facilitates task- and goal-directed behaviour, such as thinking before acting, delaying gratification, following norms and rules, and planning, organizing, and prioritizing tasks. Each of the five factors is declined into six lower-order traits, called the 30 facets (see Appendix 1), and each facet is assessed by 8 statements, that are answered on a Likert scale reflecting the individual’s approval with each statement. The NEO PI-R was originally
developed in the United States. Since its creation, the five factors have been normed and validated in several languages and cultures, and the French version of the instrument presents solid and well-documented psychometric qualities (Rolland, 1998; Rolland et al., 1998). The French NEO PI-R has been validated in an adult French-speaking Swiss sample (Rossier et al., 2001) confirming its factorial structure.
Five-Factor Theory and aging
According to Costa, Metter and McCrae (1994), personality traits are formed through childhood and reach maturity in early adulthood around age 30. Developmental approaches currently distinguish several types of continuity and change, as will be detailed. Empirical data confirmed a structural continuity of the five factors, namely the persistence of their pattern over time or across age groups (Roberts et al., 2008). Structural continuity seems to be maintained from late adolescence to late middle age (Allemand et al., 2008), yet the consistency of this continuity in old age is still matter of debate (Mroczek et al., 1998).
Four main indices for continuity are reported as summarized in Figure 2 by Roberts et al.
(2008). First, rank-order consistency addresses the relative ranking of individuals on the population level. This ranking becomes more and more consistent in longitudinal studies and reaches its maximum at age 50 (Roberts & DelVecchio, 2000; Bazana & Stelmach, 2004).
Personality factors remain moderately to highly stable over 5 to 10 years, yet the longer the timespan, the lower the consistency (Fraley & Roberts, 2005).
Figure 2: adapted from Roberts et al. (2008): organizational scheme for the basic indices of continuity and change
Relative Absolute
Population Rank-order consistency Mean-level change
Individual Ipsative consistency Individual differences in change Structural Consistency
Second, mean-level changes on the population level measure the absolute rather than the relative standing on the population level. They show an overall maturity pattern in the general population. Middle aged adults and sometimes even old age subjects continue to develop their personality dimensions, scoring higher on Agreeableness and Conscientiousness and lower on Neuroticism, and Openness than younger adults in
longitudinal studies (McCrae et al., 2000) and cross-sectional studies (Srivastava et al., 2003; Terracciano et al., 2005). In respect to Extraversion, controversy in results may reflect differential evolutions according to specific lower-order Extraversion facets: social vitality decreased with age, whilst social dominance increased, as discussed in a cross-sectional study on 2500 participants by Allemand et al. (2008). Very few studies on personality traits and old age included participants aged more than 80 years, and results reached no consensus regarding age differences between young-old (65-80 years) and old-old (80-100 years) individuals. A 6-year longitudinal study on 223 adults aged 55-85 years (Small et al., 2003) showed negative relationships between oldest-old age and personality traits may it be Conscientiousness, Openness to experience or Agreeableness, while others showed increase in Neuroticism, Agreeableness or Openness. In contrast, a cross-sectional study on 1084 adults aged 65-100 years (Weiss et al., 2005) found no evidence for age differences. A cross-sectional study on centenarians reported low levels of Neuroticism, but high levels of Extraversion, Conscientiousness and Agreeableness (Martin et al., 2006), revealing further that exceptional survivors show several unique single traits.
Third, on the individual level, ipsative continuity addresses the relative consistency within the individual over time, an analogue to the rank-order consistency but on the individual level as synthesized by Roberts et al. (2008). Interestingly, higher individual stability was associated with higher mean levels of personality factors themselves. Individuals with personality profiles associated with maturity (low level of Neuroticism - reflecting emotional stability - with high levels of Agreeableness and Conscientiousness) showed more stable personality patterns compared to those who score reversely on these factors (Roberts et al., 2008).
Finally, intra-individual differences in individual change are examined at the level of the individual in absolute terms (analogue of mean-level changes). These individual differences reflect each person’s unique pattern of increasing, decreasing, or not changing in any of the five dimensions. These changes are especially interesting for mental health clinicians to assess whether life experiences or treatment outcomes are associated with changes in personality. Individual differences in personality trait changes have been reported in adulthood as well as in old age (Mroczek & Spiro, 2003; Small et al., 2003). These non- normative patterns of change are determined by life experiences, such as marriage, death of spouse or memory complaints, as shown in a 12-year follow-up study on 1600 elderly men (Mroczek & Spiro, 2003). Individuals may compensate for physiological, psychological and social losses in old age and adjust their beliefs and attitudes to critical life events such as retirement (Roberts et al., 2008).
Five-Factor Theory in clinical samples
The five personality dimensions have been repeatedly related to physical health, to academic and work outcomes, as well as to social behaviours, but they have also emerged as powerful clinical tools for mental health professionals. They may give a useful portrait of patients’ feelings and needs and help therapists to formulate treatment plans and anticipate opportunities and pitfalls (Bagby et al., 2008; Miller, 1991). According to Costa and McCrae, the five personality dimensions are assumed to underlie both normal and abnormal personality characteristics and the Five-Factor Theory has gained recognition as a valid model for use in adult psychiatric samples (Lynam & Widiger, 2001; Rossier & Rigozzi, 2008). Replication of the five-factor structure itself has been made in a diagnostically heterogeneous group of 176 psychiatric patients (including 90 patients with major depression), showing that the same personality dimensions that accurately describe healthy adults are also found in psychiatric patients (Bagby et al., 1999). Results showed good internal reliability and factor replicability. On three of the five dimensions, patients scored at least one standard deviation above or below the mean of the normative sample, showing higher Neuroticism, and lower Extraversion and Conscientiousness, supporting the assumption that personality dimensions in psychiatric samples are extreme variants of non- clinical dimensions of personality in the general population.
Researchers as well as clinicians aim at understanding how personality combines with life experiences, demographic, comorbid physical and mental illness and psychosocial background variables to influence behaviour and thought patterns.
Personality and depression
Depression is one of the most prevalent mental disorders affecting elderly persons in Europe (Wittchen & Jacobi, 2005), however it often remains undetected or undertreated (Kohn &
Epstein-Lubow, 2006). Although the prevalence in older populations is generally lower than in younger populations (varying between 5 and 20%), it still reaches 15% in western countries, and it has been associated with increased mortality, morbidity, poor quality of life, and more frequent use of health services (Blazer, 2003; Copeland et al., 2004; Jorm, 2000;
Richards, 2011). Traditionally, a first episode of depression after the age of 60 years was thought to be associated with increased neurological and vascular impairments (Soremekum et al., 2010; Paranthaman et al., 2011). In contrast, the recurrent nature of depressive episodes in early-onset patients is mostly framed in terms of a bio-psycho-social approach, even in old age (Karel, 1997; Brodaty et al., 2001; Grace & O’Brien, 2003; Arean &
Reynolds, 2005; Blazer & Hybels, 2005). However, while personality dimensions have been repeatedly related to the multi-facet nature of the depressive disorder in younger patients, it remains unclear how this association holds across the life span.
Theories of general psychology such as the five factors of personality offer a refined description of the relationships between personality dimensions and depressive disorders.
They allow for analysing their shared and distinct components, such as the much-debated overlap between depression and Neuroticism for example (Duggan et al., 2003). In younger patients, latest overviews (Klein et al., 2011; Kotov et al., 2010; Widiger & Smith, 2008) mainly distinguished three forms of potential interplay between personality and depression.
Precursor models consider that personality is an early manifestation of depression and they both may share similar etiological influences and are conceived on the same continuum.
Depression is thought to identify individuals who have the most extreme scores on a relevant trait. Predisposition or vulnerability models posit that personality plays a causal role in the onset of depression. The most cited of these models is the diathesis-stress model (Klein et al., 2011), which hypothesis that stress moderates the influence of personality to precipitate the onset of depression, where depressive episodes have an enduring effect on personality, with alterations persisting even after recovery (complication or scar models).
Pathoplasticity models also consider that personality has a causal influence on depression, yet personality is thought to influence the expression of depression after onset, namely the severity of the symptoms, their course and their response to treatment. This relationship is considered to be bidirectional, and psychopathology is expected to differ in its appearance depending on patients’ premorbid personality traits. Depression is experienced differently depending on the person’s level of Neuroticism and Extraversion for example. In return, the expression of personality can be affected by the presence of a comorbid depression.
Pathoplasticity is the model chosen to generate the hypotheses of the present study, with a focus on a unidirectional influence of personality on depression.
Longitudinal evidence
With regard to depression outcome and its prediction by personality factors, the need for longitudinal study designs is evident. The empirical validation of one of these models would be clearly beyond the scope of the present study. Nevertheless, previously published longitudinal results on depression outcome offer precious working hypotheses on the differential impacts of the five factors.
In younger adults, most studies suggested that high Neuroticism, low Conscientiousness, and to a lesser extent low Extraversion, predict a poorer course and response to treatment (Bock et al., 2010; De Fruyt et al., 2006; Morris et al., 2009; Quilty et al., 2008). Individuals more sensitive to negative mood may draw less benefit from pleasant activities and be more resistant to a change in mood, whereas individuals more outgoing, friendly and open towards others may be more likely to enjoy social relationships and activities. Moreover, patients with low levels of Conscientiousness, who lack the efficient processes of planning, organizing and carrying out tasks, may experience more difficulties in improving oppressive living conditions or relationships, and self-perpetuate inconsistent or inadequate performances (Costa & McCrae, 1992). Although intuitively acceptable, the impact of personality disorders on poor response to antidepressant pharmacotherapy remains controversial (Kool et al., 2005; Newton-Howes et al., 2006). Similarly, the influence of personality disorders or traits in non-pharmacological treatment outcome may vary according to the nature of therapy (Joyce et al., 2007). Both medication and psychotherapy responders have demonstrated lower Neuroticism, and higher Extraversion and Openness scores compared to non-responders (Quilty et al., 2008). In respect to pharmacological compliance, Extraversion has been shown to be a stronger negative predictor than depression severity or side effects (Cohen et al., 2004).
In old age, evidence on the relationship between personality dimensions and treatment outcome is still rare. Data on individual differences distinguishing responders from non- responders are lacking and evidence is drawn from large randomized trials and meta- analyses, which fatally blur individual differences. In a prospective 9 years follow-up study of 206 adults aged 55 to 85 years, Steunenberg et al. (2007) reported low Neuroticism to be a strong predictor of the recovery of depressive symptoms. Higher self-esteem - one of the Conscientiousness facets of the Five Factor Theory - was associated with faster temporal response to pharmacological treatment in late-life depression in 395 elderly patients (Gildengers et al., 2005). However, no such relationship was documented when pharmacological treatment was combined with weekly interpersonal psychotherapy.
Emerging data showed that personality is a key factor to consider when planning both community-based and psychotherapeutic interventions in the elderly (Canuto et al., 2008, 2009). Lower levels of Neuroticism significantly predicted better clinical outcome (decrease of depressive symptoms and increase in health-related quality of life) of a psychogeriatric day hospital treatment combining individual and group psychotherapy with psychopharmacology in 62 depressed outpatients in a 12-month follow-up. Weis et al.
(2005) investigated whether the five personality factors were related to incident major depression in 512 community dwelling older adults (65-100 years) with disability in a 22-
month follow-up. These authors postulated that depression may be the result of a particular combination of several factors, defined as a personality “style”. Higher Neuroticism and lower Conscientiousness emerged as risk markers. Yet, Extraversion, Openness, and Conscientiousness played a role in determining whether high Neuroticism was related to incident major depression. Similarly, low levels of Extraversion, Openness, and Agreeableness amplified the risk of low Conscientiousness for depression. Adults with the combination of high Neuroticism and low Conscientiousness revealed to be the most vulnerable to develop depression. Authors explained that the dispositional difficulty with impulse control of these individuals makes them particularly vulnerable to the deleterious effects of poor self-management of health concerns. Low Conscientiousness is thought to augment the influence of Neuroticism while high Conscientiousness may mitigate it.
Cross-sectional evidence
A large number of cross-sectional studies have also evaluated the relationship between depression and the five personality dimensions. In their pioneer work, Clark et al. (1994) have first described the association between the presence of acute depressive symptoms and high levels of Neuroticism as well as low levels of Extraversion in younger cohorts.
Recent meta-analyses confirmed a strong cross-sectional relationship between major depression and high Neuroticism and low Conscientiousness respectively, yet reported only a modest and inconsistent relationship with low Extraversion, and no significant associations with Agreeableness and Openness to experience (Klein et al., 2011; Kotov et al., 2010).
With regard to Extraversion, these reviews stressed the fact that studies focusing on lower- order traits rather than the broad personality dimensions promised to reveal stronger and more specific evidence of personality and depression association. Indeed, Klein et al. (2011) reported that unlike sociability facets, the positive affectivity facet of Extraversion was negatively related to depression. Further, these meta-analyses revealed that the relationship between depression and personality factors differed according to the different forms of depression. For example, the relationship was stronger in dysthymic disorders compared to major depression. Data on the relationship between personality dimensions and late-life depression are clearly less abundant. The majority of studies in the elderly revealed that family history and personality abnormalities are more common in patients with early-onset depression (age at onset of the first major depressive episode before 60 years), in contrast to more frequent vascular vulnerabilities in late-onset depression (Brodaty et al., 2001;
Grace & O’Brien 2003). These authors hypothesized potentially different interplays between personality and depression on the basis of distinct etiopathogenesis between early- and late-
onset depression (Papazacharias et al., 2010). Personality appears to be most strongly related to early-onset, chronic, and recurrent depressive episodes.
Several criticisms raised the doubt about the cross-sectional personality-psychopathology relationships because it may be complicated by the influence of patient’s mood state on the self-reported questionnaires of their personality (Klein et al., 2011). Personality assessments often cover state affect as well as trait variances, the variance of the first masking the variance of the second during acute episodes (Clark et al., 2003). Depressed patients report higher levels of Neuroticism than non-depressed individuals (Kendler et al., 2006) and critics argue that changes in self-reported personality measures are merely a depression related measurement bias. Whether or not these higher levels are only state or also trait markers of depression in young age remains indeed unsolved (Griens et al., 2002; Santor et al., 1997).
However, in their meta-analyses, Klein et al. (2011) concluded that state effects couldn’t fully account for the associations between personality and depression. Tang et al. (2009) examined the state effect hypothesis in 240 adult moderately to severely depressed patients randomly receiving pharmacotherapy, placebo or cognitive therapy. Patients receiving treatment self-reported higher Neuroticism and Extraversion changes than placebo patients matched for observer-rated depression improvement. Although placebo patients showed substantial depression improvement, they reported little change. Cognitive therapy produced greater personality changes than placebo, but its advantage on Neuroticism was no longer significant after controlling for depression. The authors conclude that pharmacotherapy seems to have a specific effect on personality that is distinct from its effect on depression.
Indeed, other studies showed that even though levels of Neuroticism decreased after remission (de Fruyt et al., 2006; Morey et al., 2010), they did not reach the normal range. In contrast, state-dependent changes in Extraversion are less consistent (de Fruyt et al., 2006;
Kendler et al., 1993), and Klein et al. (2011) concluded that Extraversion is not dependent on the mood state. This factor has been found to be significantly lower in remitted patients than in never-depressed controls (Hirschfeld et al., 1983), possibly confounding personality and residual symptoms. Unfortunately, most of the studies compared their patients to normative data, without using a matched control group and without controlling for socio- demographic differences between patients and comparison groups (Klein et al., 2011).
Regarding old age depression, studies have revealed differences in personality dimensions compared to controls in the absence of acute depressive states. Twenty years ago, Abrams et al. (1991) had reported higher scores of Neuroticism (but no change in Extraversion) in 16 elderly patients that recovered from depression compared to 14 controls. In a recent cross- sectional comparison (Weber et al., 2010), we showed that unlike neuropsychological
performances and volumetric MRI data, increase in Neuroticism and decrease of Extraversion facets allowed for distinguishing euthymic older patients with depression from healthy controls.
Personality, depression and quality of life
Utilization of health services is more influenced by how patients feel than by their objective symptoms. Research has shown that compliance and satisfaction with treatment depends on their impact on the patients’ well-being (Hunt & McKenna, 1992; Stedman, 1996). These findings increased the interest in assessing the patients’ perception of their disease, leading health care to gradually evolve form a paternalistic reduction of illness (where specialists are considered to have the key for recovery) to the improvement of the subjective well-being (where patients actively take part in the healing process and responsibility) (Böckerman et al., 2011). Böckerman et al. (2011) found that the impact of psychiatric disorder on life satisfaction was found to be significantly higher (two-fold), compared to chronically invalidating diseases such as musculoskeletal conditions. Seeking to measure the patients’
subjective experience, well-being measures were recently introduced as an additional outcome variable in this field of depression outcome research. They also provide additional information about timelines for improvement in psychosocial functioning, which may occur at a different rate than changes in depressive symptoms (Kennedy et al., 2001).
According to Lucas and Diener (2008), subjective well-being reflects the extent to which individuals think and feel that their life goes well. Camfield and Skevington (2008) pondered that subjective well-being and quality of life are virtually synonymous, and considered life satisfaction to be equally nested within both concepts. According to the World Health Organization, subjective quality of life is defined as the individuals’ perception of their position in life in the context of their culture and value system and in relation to their goals, expectations, standards and concerns. It is classically assessed as a multidimensional concept aggregating well-being across several life domains: physical, psychological, social and environmental (WHOQOL Group, 1998). Quality of life is considered a complex interplay between internal and external factors and therefore of special interest for mental health professionals. Amongst the internal factors, personality seems to play a key role for subjective well-being (Masthoff et al., 2007). In the general population, subjective well-being is more strongly related to specific personality traits than demographic predictors or major life circumstances (Lucas & Diener, 2008) as will be discussed further.
Quality of life measures have been assessed in younger depressed and psychiatric patients.
Common psychiatric disorders such as depressive disorders, alcohol use and anxiety disorders decreased subjective well-being (Böckerman, et al., 2011). In a prospective longitudinal 8-year follow-up including 157 patients, depressive symptoms have been associated to poor quality of life, independently of illness chronicity, medication use, or affective disorder subtype (Goldberg & Harrow, 2005). A cross-sectional comparison of well- being in 100 patients with major depression and 61 healthy controls aged about 50 years (Pyne et al., 1997) revealed that quality of life was best predicted by depressive symptoms severity (Hamilton Rating Scale for Depression and Beck Depression Inventory). Results of follow-up studies showed a rapid improvement in quality of life after 8 weeks of antidepressant treatment in 106 moderately depressed adults treated by their general practitioners (Skevington & Wright, 2001), while the long-term effect remain questioned.
Patients with remitted depression reported worse quality of life than normal controls six months after hospital discharge (Angermeyer et al., 2002). Concerning their relationship with personality, in a cross-sectional study on 495 psychiatric outpatients aged 21-50 years from a community mental health centre, Neuroticism showed the strongest negative and Extraversion the strongest positive relationship with quality of life (as assessed by the WHOQOL-100). Amongst the remaining personality domains, Conscientiousness had positive relationships with quality of life, whereas Openness and Agreeableness were not significantly related to quality of life. In addition, age explained only a small amount of additional quality of life variance, and gender played no role at all (Masthoff et al., 2007).
In older clinical samples, fewer studies are available on the depression and well-being relationship. Nevertheless, quality of life may be a particularly valuable marker of well-being in elderly with depression (Gurland, 1992). Existing studies showed that major depression emerges as a main predictor of decreased quality of life, older depressed adults having lower perceived quality of life than non-depressed controls (Chan et al., 2006; Doraiswamy, 2002; Naumann & Byrne, 2004). In 350 older nursing-home patients, depression and anxiety have been associated with a more than 25% decrease in well-being measures and higher consumption of medical care (Smalbrugge et al., 2006). Further, depressive symptoms predicted decreased subjective well-being in community-based adults in 194 participants aged 75+ in Israel (Landau & Litwin, 2001) and 800 adults aged 60 to 100 years in the United States (Waddell & Jacobs-Lawson, 2010). Even minor levels of depression have been related to quality of life decrease in a large cross-sectional study on 4316 individuals in 20 countries (Chachamovich et al., 2008). Taken together, the association of quality of life and depressive symptoms seems to hold independently of patients’ age. Regarding the relationships between personality, quality of life and depression, few reports have controlled
for observer-rated depression and studies have mostly not controlled for whether age moderated the effect of personality on quality of life. Uniquely, Duberstein et al. (2003) found that the relationship between personality and subjective quality of life (as assessed by the Medical Outcomes SF-36 Short Form Health Survey) prevailed even after controlling for observer-rated depression in 265 primary care patients aged 60+ years. High Neuroticism and low Extraversion were related to poorer perceived quality of life, while low Openness was associated with worse self-rated functional status as defined by the capacity to perform activities of daily living.
In parallel, in studies in non-clinical samples, the broad personality domains, such as defined by the Five-Factor Theory, are substantial predictors of subjective well-being, both in young (Costa & McCrae, 1980; DeNeve & Cooper, 1998; Steel et al., 2008) and in old adults (Keyes et al., 2002; Landau & Litwin, 2001; Ryff, 2008). Thirty years ago, Costa and McCrae (1980) proposed a model of happiness that posits two independent components to be subjectively balanced by each individual to create a sense of subjective well-being, as illustrated by Figure 3.
Figure 3: adapted from Costa & McCrae (1980): a model of personality influences on positive and negative affect on subjective well-being
These authors considered that two sources of variation operate to produce two independent effects, and they are thought to lie within the person, Neuroticism and Extraversion being prime candidates, as has been confirmed later (DeNeve & Cooper, 1998; McCrae & Costa, 1991) in younger adults. Lower levels of Neuroticism (or emotional stability) have been shown to be an even stronger correlate and accounting for a higher percentage of variance of subjective well-being than Extraversion (Libran, 2006). Among the remaining personality factors, Openness to experience showed no effect on well-being (McCrae & Costa, 1991).
High levels of Openness characterize individuals who have a broader and deeper range of EXTRAVERSION:
sociability, tempo, vigor, social involvement
NEUROTICISM: anxiety, hostility, impulsivity, psychosomatic complaints
Positive affect:
satisfaction
Negative affect:
dissatisfaction
Subjective well-bing
“Happiness”: morale, life satisfaction, hopefulness, affect balance
awareness, imagination, and curiosity, and who experience more intensely the positive as well as the negative effects. Openness does not have an affect-biasing influence as Neuroticism and Extraversion, but amplifies the experience of both kinds of affects. Further, McCrae and Costa (1991) qualified the relationship of Agreeableness and Conscientiousness with well-being as instrumental, creating conditions that may promote well-being. Agreeable individuals are warm, generous and loving, fostering interpersonal relationships. Conscientious individuals are efficient, competent, and hardworking, promoting achievements and accomplishments that contribute to higher levels of quality of life. These two factors may thus indirectly enhance well-being.
Studies addressing well-being and aging revealed that high levels of Extraversion predicted constant high life satisfaction. Lower levels of this factor predicted more curved trajectories with high life satisfaction in midlife but low life satisfaction in young and old age (Mroczek &
Spiro, 2003). Overall, data suggested that high Extraversion and Conscientiousness and low Neuroticism are among the best predictors of well-being and health in old age (Baltes &
Mayer, 1999; Friedman, 2000; Samuelssen et al., 1997). Extraversion is linked to positive health behaviour and lower expression of psychological and physical symptoms. In contrast, Neuroticism has been associated with more reports of psychological symptoms, poorer perceived health, more health complaints, more self-focused attention and preoccupation, and a lower level of psychological well-being (Gilhooly et al., 2007; Jerram & Coleman, 1999; Woodruff-Borden et al., 2001). Personality factors may also interact to predict longitudinal change in well-being (Bardi & Ryff, 2007). Openness amplifies the positive respectively negative effects of Neuroticism and Extraversion on well-being, while Extraversion interacts with Conscientiousness and Agreeableness to predict changes in well-being.
It is, however, necessary to distinguish between hedonic and eudemonic aspects of well- being when addressing aging (Ryff, 2008). Keyes et al. (2002) considered the role of personality factors in predicting different combinations of well-being. Hedonic well-being focuses on satisfaction, happiness and positive affect, in contrast to eudemonic or psychological well-being, which assesses purpose and meaning in life as well as self- realization and growth. Optimal well-being, namely both higher hedonic and eudemonic well- being has been shown to have a positive relationship with aging and is positively predicted by Extraversion and Conscientiousness and negatively by Neuroticism. Higher eudemonic well-being without hedonic well-being was positively predicted by higher Openness to experience, and has been shown to decrease in aging. Overall, results on Openness and
quality of life were less consistent than for Neuroticism and Extraversion, while Conscientiousness seemed positively related to quality of life (Brett et al., 2011).
Integrative approach
This section reviews studies that have analysed the complex associations between personality, depression and quality of life taking into account demographic, psychosocial and physical health variables. As illustrated by Ryff (2008), interest in depression and well-being research has evolved from social surveys looking for objective external indicators to psychosocial correlates and psychological indicators and mechanisms. Related to this shift of interest, the multivariate approach is becoming a dominant feature in subjective well-being studies. The current research challenge is to adopt an integrative approach that concomitantly assesses demographic and psychosocial background variables together with individual markers of psychological vulnerability such as personality factors, when studying age-specific interfaces of depression and well-being.
Integrative approaches in young age
In younger patients, major depression is typically considered as a complex, multi-factorial disorder. Etiological variables that have been studied classically include gender, genetic vulnerabilities, developmental events (exposure to disturbed family environment or traumatic life events), recent stressful life events and difficulties, physiological stressors, low social support, as well as personality traits (Kendler et al., 1993; 2002). Some reviews have attempted to incorporate these different risk and protective factors into a developmental model of depression. Kendler et al. (2002) suggested three pathways leading to depression.
The internalizing pathway that is anchored by Neuroticism and early-onset anxiety disorder, an externalizing pathway that is anchored by conduct disorder and substance abuse, and finally an adversity pathway that includes childhood risk factors, low level of education and low social support as well as recent stressful life events. With regard to interpersonal relationships, Kendler described social support as having indirect effects. Individuals, who have experienced their parents as loving and trusting, might be more able to form stable and mutually supportive long-term relationships with a marital partner, which in returns acts as a protective factor on depression. Genetic factors seemed to play an important etiological role essentially in lifetime prevalence, and have been considered the second risk factor, just after recent stressful life events (Kendler et al., 1993). On the other hand, personality was a robust predictor of future episodes (Kendler et al., 1993). In particular, high Neuroticism increased the risk for subsequent episodes of major depression. However, another study
