1 Introduction and Background
1.2 Overview of Scenarios
The following section provides further details on each of the hypothetical interventions tested in the model including key assumptions. Each of the scenarios described below were simulated and compared to the baseline model over a thirty year time frame, from 2011 to 2041. For more information on the baseline model please refer to Smetanin et al. (2011).
All-Cause Incidence
The all-cause incidence scenario examined the impact of reducing the overall all cause incidence of mental illness across each of the major mental illnesses in Canada including mood disorders, anxiety disorders, schizophrenia, SUD, dementia, CD, ODD and ADHD. The annual incidence rate of each illness was reduced by 10% to examine the impact on 12-month prevalence, total direct and indirect costs
6 Note that for this analysis it was assumed that an increase in remission rates had no impact on cognitive impairment including dementia.
Page | 24 relative to the baseline model. It is important to note that all other model parameters remained unchanged from the baseline and that existing prevalent cases were not altered. It was only the incidence rate of new cases that was adjusted.
Prior Mental Illness in Childhood or Adolescence
This risk reduction scenario examined the impact of reducing the risks associated with prior mental illness in childhood and adolescence for all major mental illnesses in Canada. This hypothetical intervention assessed the impact of decreasing the relative risks associated with a prior mental illness in youth by 10% on 12-month prevalence7, total direct and indirect costs against the baseline model. This scenario included two parts:
1. A 10% reduction in the risks associated with incidence of any adolescent mental illness given a childhood mental illness; and
2. A 10% reduction in the risks associated with any adult mental illness given an adolescent mental illness.
As in the incidence reduction scenario, the existing prevalent cases were not altered at the time of the intervention. The relative risks of an adolescent mental illness given prior childhood illness from our baseline model are shown in Table 3.
7 Note that it is the excess risk above one that is reduced by 10%, not the total value of the relative risk factor.
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Table 3 Baseline Model: Relative Risk of Adolescent Mental Illness Given Prior Childhood Illness
The relative risks of an adult mental illness given prior adolescent illness from our baseline model are shown in Table 4.
Table 4 Baseline Model: Relative Risk of Adult Mental Illness Given Prior Adolescent Illness
Table 5 and Table 6 provide the 10% reduction in the relative risk estimates associated with the incidence of any adolescent mental illness given a childhood mental illness and the risk of any adult mental illness given an adolescent mental illness, respectively.
Prior Childhood
Illness ADHD Anxiety
Conduct Disorders
Mood
Disorders ODD SUD
ADHD - 1.66 1.89 1.99 4.99 2.88
Anxiety 4.14 - 2.22 2.93 2.47 1.34
Conduct Disorders 6.54 1.09 - 1.23 3.50 3.38
Mood Disorders 4.28 3.33 3.31 - 4.09 2.45
ODD 4.06 2.33 3.18 2.30 - 3.09
ADHD - 1.60 1.92 1.92 4.98 3.17
Anxiety 5.10 - 2.27 2.78 2.50 1.37
Conduct Disorders 9.46 1.08 - 1.22 3.53 3.92
Mood Disorders 5.39 3.00 3.45 - 4.17 2.71
ODD 5.01 2.17 3.30 2.20 - 3.54
Adolescent Illness
Male
Female
Prior Adolescent
Illness Anxiety
Mood
Disorders SUD Anxiety
Mood
Disorders SUD
ADHD 2.21 1.23 2.23 2.00 1.22 2.52
Anxiety - 2.43 1.04 - 2.33 1.05
Conduct Disorders 1.78 1.74 2.81 1.67 1.69 3.46
Mood Disorders 3.05 - 1.38 2.70 - 1.44
ODD 2.74 2.08 1.84 2.40 1.99 2.03
SUD 2.59 1.88 - 2.31 1.81
-Adult Illness - Male Adult Illness - Female
Page | 26
Table 5 Scenario Model: Relative Risk of Adolescent Mental Illness Given Prior Childhood Illness
Table 6 Scenario Model: Relative Risk of Adult Mental Illness Given Prior Adolescent Illness
Remission Rates
The remission rate scenario examined the potential impact of increasing remission rates for all major mental illnesses in Canada by 10% over the baseline model, on 12-month prevalence, total direct and indirect costs. It is important to note that the model assumed no remission rates for those with cognitive impairment including dementia. It is also important to note that increasing remission rates do necessarily reduce the number of people living with mental illness but rather reduces the effects associated with mental illness, improving overall health and the costs associated with treatment of mental illness.
Prior Childhood
Illness ADHD Anxiety
Conduct Disorders
Mood
Disorders ODD SUD
ADHD - 1.59 1.80 1.89 4.59 2.69
Anxiety 3.83 - 2.10 2.74 2.33 1.31
Conduct Disorders 5.99 1.08 - 1.21 3.25 3.15
Mood Disorders 3.95 3.09 3.08 - 3.78 2.31
ODD 3.75 2.20 2.96 2.17 - 2.88
ADHD - 1.54 1.82 1.82 4.58 2.96
Anxiety 4.69 - 2.14 2.60 2.35 1.34
Conduct Disorders 8.61 1.07 - 1.20 3.28 3.63
Mood Disorders 4.95 2.80 3.21 - 3.85 2.54
ODD 4.61 2.06 3.07 2.08 - 3.29
Adolescent Illness
Male
Female
Prior Adolescent
Illness Anxiety
Mood
Disorders SUD Anxiety
Mood
Disorders SUD
ADHD 2.09 1.21 2.11 1.90 1.19 2.37
Anxiety - 2.29 1.04 - 2.20 1.04
Conduct Disorders 1.70 1.67 2.63 1.60 1.62 3.21
Mood Disorders 2.84 - 1.34 2.53 - 1.39
ODD 2.56 1.98 1.75 2.26 1.89 1.92
SUD 2.43 1.79 - 2.18 1.73
-Adult Illness - Male Adult Illness - Female
Page | 27 Economic Disability
Economic disability is a measure of how an illness affects productivity in the labour force. The economic disability scenario examined the impact of decreasing the economic disability associated with (or equivalently improving the productivity of people with) all major mental illnesses in Canada by 10% over the baseline on the total indirect economic costs. This hypothetical scenario did not directly alter the prevalence of illness in the labour force or the direct costs associated with mental illness, but assumed that people with mental illness would be 10% more productive in the labour force than in the base model.
The Combined Impact of All of the Above
The final scenario examined a combination of all of four scenarios for all major mental illness in Canada.
That is, it evaluated the combined impact of:
Decreasing the all-cause incidence of mental illness by 10%;
Increasing the remission rates by 10%;
Decreasing the relative risks associated with prior mental illness in childhood or adolescence by 10%; and
Decreasing the workplace disability associated with mental illness by 10%.
Page | 28 2 SCENARIO ANALYSIS OF MENTAL ILLNESS INTERVENTIONS
The impacts of the proposed intervention scenarios were compared to the base model results to derive the value proposition of the interventions. The following section summarizes the value proposition of each scenario over the simulation period. It is important to note that since these interventions represent hypothetical scenarios, the actual intervention programs and the costs associated with program implementation and human resource requirements were not taken into account. In addition, the hypothetical interventions may have additional benefits not taken into consideration within this analysis. These additional benefits may include, but are not limited to, improvements in activities of daily living, quality of life and comorbid health conditions, as well as benefits associated with burden placed on formal and informal caregivers. Note that the economic disability reduction scenario does not affect the incidence or prevalence of mental illness. It only affects productivity in the labour force. There results of the economic disability scenario are limited to Section 2.2.
2.1 LIFE IMPACTS OF SCENARIOS
In this section the impact of each scenario on the 12-month prevalence from 2011 to 2041 is presented for each of the mental illnesses included in the model. For detailed annual results, please refer to Appendix B.
Page | 29 2.1.1 ANY MENTAL ILLNESS
Figure 4 Estimated Number of People with Any Mental Illness (12-Month Prevalence) for the Baseline Model and Each of the Hypothetical Intervention Scenarios.
Figure 4 compares the estimated number of Canadians with any mental illness at baseline to each of the hypothetical scenarios over a 30-year simulation period. For both males and females, reducing the all cause incidence rates by 10% produces the largest reduction on the number of people living with any mental illness. The interventions affect the health state of the population through altered incidence and remission rates. The prevalence was not altered directly. As a result, the benefits of the interventions grow over time. For example, when incidence rates are reduced, those currently with a mental illness will continue with that illness until remission or death. However, over time fewer people are becoming ill than would have without the intervention resulting in a reduction in prevalence which grows over time. The estimated reduction in these numbers is shown in Figure 5. The reduction in prevalence as a percentage of the population is shown in Figure 6. Note that this is the absolute prevalence in the
Page | 30 time-frame is 30 years, a significant number of people with mental illness prior to the intervention remain alive in the model limiting the reduction in prevalence to 2.3% when all interventions are combined.
Figure 5 Estimated Reduction in Number of People with Any Mental Illness (12-Month Prevalence) for Each of the Hypothetical Intervention Scenarios.
Estimated Reduction in Number of People with Any* Mental Illness (12-Month Prevalence) for Each of the Hypothetical Intervention Scenarios
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Figure 6 Estimated Reduction in 12-Month Prevalence of Any Mental Illness for Each of the Hypothetical Intervention Scenarios.
Table 7 and Table 8 provide the short-term and long-term impacts associated with each of the hypothetical scenarios as well as the impact of combining each scenario.
Relative to the baseline model, the short-term (2011-2021) impacts are expected to yield the following results:
By increasing remission by 10%, it is estimated that 183,900 fewer Canadians will be living with the effects associated with major mental illness by 2021 (a 0.5% reduction in 12-month prevalence relative to the baseline model);
By reducing all cause incidence by 10%, there is an estimated reduction of 289,860 Canadians living with major metal illness by 2021 (a 0.8% reduction in 12-month prevalence relative to the baseline model) is expected;.
Estimated Reduction in 12-Month Prevalence of Any* Mental Illness for Each of the Hypothetical Intervention Scenarios
Remission
Page | 32 By reducing the relative risk associated with a prior mental illness in childhood or adolescence by 10%, it is estimated that 22,100 fewer Canadians will be living with a major mental illness by 2021 (a 0.1% reduction in 12-month prevalence relative to the baseline model); and
The combination of each of the above scenarios results in an estimated reduction of 488,120 Canadians living with a major mental illness by 2021 (a 1.3% reduction in 12-month prevalence relative to the baseline model).
Relative to the baseline model, the long-term (2011-2041) impacts are expected to yield the following results:
By increasing remission by 10%, 367,220 fewer Canadians were estimated to be living with the effects associated with major mental illness by 2041 (a 0.9% reduction in 12-month prevalence relative to the baseline model);
By reducing all cause incidence by 10%, it is estimated that 597,440 fewer Canadians will be living with a major mental illness by 2041 (a 1.4% reduction in 12-month prevalence relative to the baseline model);
By reducing the relative risk associated with a prior mental illness in childhood or adolescence, an estimated 40,160 fewer Canadians will be living with a major mental illness by 2041 (a 0.1%
reduction in 12-month prevalence relative to the baseline model); and
The combination of each of the above scenarios results in in an estimated reduction of 981,280 Canadians living with a major mental illness by 2041 (a 2.3% reduction in 12-month prevalence relative to the baseline model).
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Table 7 Estimated Baseline and Reduction in Number of People with Any Mental Illness (12-Month Prevalence) for the Baseline Model, and Each of the Hypothetical Intervention Scenarios.
Table 8 Estimated Baseline and Reduction in 12-Month Crude Prevalence of People with Any Mental Illness for Each of the Hypothetical Intervention Scenarios.
Estimated Reduction in Number of People with Any* Mental Illness (12-Month Prevalence) in Canada, by Scenario, 2011 to 2041
Reduction in Estimated 12-Month Prevalence of Any* Mental Illness in Canada, by Scenario, 2011 to 2041
Page | 34 2.1.2 ADHD
Figure 7 Estimated Number of People with ADHD (12-Month Prevalence) for the Baseline Model, and Each of the Hypothetical Intervention Scenarios.
Figure 7 compares the estimated number of Canadian youth with ADHD at the baseline to each of the hypothetical scenarios over a 30-year simulation period. For both males and females, reducing the all cause incidence rates by 10% produces the largest reduction on the number of youth living with ADHD.
The estimated reduction in these numbers is shown in Figure 8. The reduction in prevalence as a
Page | 35
Figure 8 Estimated Reduction in Number of People with ADHD (12-Month Prevalence) for Each of the Hypothetical Intervention Scenarios.
-5,000 10,000 15,000 20,000 25,000
2011 2016 2021 2026 2031 2036 2041
Reduction in Number of Canadians
Estimated Reduction in Number of People with ADHD (12-Month Prevalence) for Each of the Hypothetical Intervention Scenarios
Remission Incidence RR Combined
-5,000 10,000 15,000 20,000 25,000
2011 2016 2021 2026 2031 2036 2041
Reduction in Number of Canadians
Estimated Reduction in Number of People with ADHD (12-Month Prevalence) for Each of the Hypothetical Intervention
Scenarios- Male
Remission Incidence RR Combined
-5,000 10,000 15,000 20,000 25,000
2011 2016 2021 2026 2031 2036 2041
Reduction in Number of Canadians
Estimated Reduction in Number of People with ADHD (12-Month Prevalence) for Each of the Hypothetical Intervention
Scenarios- Female
Remission Incidence RR Combined
Page | 36
Figure 9 Estimated Reduction in 12-Month Prevalence of ADHD for Each of the Hypothetical Intervention Scenarios.
Table 9 and Table 10 provide the short-term and long-term impacts associated with each of the hypothetical scenarios as well as the impact of combining each scenario.
Relative to the baseline model, the short-term (2011-2021) impacts are expected to yield the following results:
By increasing remission by 10%, an estimated 3,360 fewer Canadian youth will be living with the effects associated with ADHD by 2021 (a 0.13% reduction in 12-month prevalence relative to the baseline model);
By reducing all cause incidence by 10%, it is estimated that 15,690 fewer Canadian youth will be living with ADHD by 2021 (a 0.69% reduction in 12-month prevalence relative to the baseline
Page | 37 By reducing the relative risk associated with a prior mental illness in childhood or adolescence by 10%, it is estimated that 150 fewer Canadian youth will be living with ADHD by 2021 (a 0.01%
reduction in 12-month prevalence relative to the baseline model); and
The combination of each of the above scenarios results in an estimated reduction of 18,920 Canadian youth living with ADHD by 2021 (a 0.82% reduction in 12-month prevalence relative to the baseline model).
Relative to the baseline model, the long-term (2011-2041) impacts are expected to yield the following results:
By increasing remission by 10%, an estimated 4,040 fewer Canadian youth will be living with the effects associated with ADHD by 2041 (a 0.14% reduction in 12-month prevalence relative to the baseline model);
By reducing all cause incidence by 10%, it is estimated that 19,170 fewer Canadian youth will be living with ADHD by 2041 (a 0.73% reduction in 12-month prevalence relative to the baseline model);
By reducing the relative risk associated with a prior mental illness in childhood or adolescence by 10%, it is estimated that 170 fewer Canadian youth will be living with ADHD by 2041 (a 0.1%
reduction in 12-month prevalence relative to the baseline model); and
The combination of each of the above scenarios results in an estimated reduction of 22,980 Canadian youth living with ADHD by 2041 (a 0.86% reduction in 12-month prevalence relative to the baseline model).
Page | 38
Table 9 Estimated Baseline and Reduction in Number of People Aged 9 to 19 Years with ADHD (12-month prevalence) for the Baseline Model, and Each of the Hypothetical Intervention Scenarios.
Table 10 Estimated Baseline and Reduction in 12-Month Crude Prevalence of People Aged 9 to 19 Years with ADHD for Each of the Hypothetical Intervention Scenarios.
Year Increase Remission Reduce Incidence
Reduce Relative Risk
Combined Intervention 2021 176,185 3,367 15,693 152 18,929 2031 193,039 3,894 18,496 172 22,162 2041 200,220 4,046 19,179 178 22,987 2021 153,399 2,942 13,585 126 16,408 2031 168,107 3,403 16,001 143 19,201 2041 174,359 3,536 16,592 148 19,916 2021 22,786 424 2,108 - 2,520 2031 24,932 491 2,494 - 2,961 2041 25,861 510 2,587 - 3,071 Total
Male
Female
Impact of Different Intervention Scenarios on the Estimated Number of People with ADHD (12-Month Prevalence) Aged 9 to 19 Years in Canada, by Scenario, 2011 to 2041
Baseline Number of People
Reduction in Number of People in each Scenario
Year Increase Remission Reduce Incidence
Reduce Relative Risk
Combined Intervention
Total 2021 7.62% 0.13% 0.69% 0.01% 0.82%
2031 7.63% 0.14% 0.73% 0.01% 0.86%
2041 7.62% 0.14% 0.73% 0.01% 0.86%
Male 2021 12.94% 0.23% 1.16% 0.01% 1.38%
2031 12.95% 0.24% 1.23% 0.01% 1.46%
2041 12.93% 0.24% 1.23% 0.01% 1.46%
Female 2021 2.02% 0.03% 0.19% - 0.22%
2031 2.02% 0.04% 0.20% - 0.24%
2041 2.02% 0.04% 0.20% - 0.24%
Reduction in Estimated 12-Month Prevalence of ADHD in People Aged 9 to 19 Years in Canada, by Scenario, 2011 to 2041
Baseline 12-Month Prevalence
Reduction in 12-Month Prevalence Scenario
Page | 39 2.1.3 ODD
Figure 10 Estimated Number of People with ODD (12-Month Prevalence) for the Baseline Model, and Each of the Hypothetical Intervention Scenarios.
Figure 10 compares the estimated number of Canadian youth with ODD at the baseline to each of the hypothetical scenarios over a 30-year simulation period. For both males and females, reducing the all cause incidence rates by 10% produces the largest reduction in the number of youth living with ODD.
The estimated reduction in these numbers is shown in Figure 11. The reduction in prevalence as a percentage of the population is shown in Figure 12.
75,000 80,000 85,000 90,000 95,000 100,000
2011 2016 2021 2026 2031 2036 2041
Number of Canadians
Estimated Number of People with ODD (12-Month Prevalence)
Base Case Remission Incidence RR Combined 30,000
35,000 40,000 45,000 50,000 55,000 60,000
2011 2016 2021 2026 2031 2036 2041
Number of Canadians
Estimated Number of People with ODD (12-Month Prevalence)- Male
Base Case Remission Incidence RR Combined
30,000 35,000 40,000 45,000 50,000 55,000 60,000
2011 2016 2021 2026 2031 2036 2041
Number of Canadians
Estimated Number of People with ODD (12-Month Prevalence)- Female
Base Case Remission Incidence RR Combined
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Figure 11 Estimated Reduction in Number of People with ODD (12-Month Prevalence) for Each of the Hypothetical Intervention Scenarios.
-2,000 4,000 6,000 8,000 10,000 12,000 14,000
2011 2016 2021 2026 2031 2036 2041
Reduction in Number of Canadians
Estimated Reduction in Number of People with ODD (12-Month Prevalence) for Each of the Hypothetical Intervention Scenarios
Remission Incidence RR Combined
-1,000 2,000 3,000 4,000 5,000 6,000 7,000
2011 2016 2021 2026 2031 2036 2041
Reduction in Number of Canadians
Estimated Reduction in Number of People with ODD (12-Month Prevalence) for Each of the Hypothetical Intervention
Scenarios- Female
Remission Incidence RR Combined
-1,000 2,000 3,000 4,000 5,000 6,000 7,000
2011 2016 2021 2026 2031 2036 2041
Reduction in Number of Canadians
Estimated Reduction in Number of People with ODD (12-Month Prevalence) for Each of the Hypothetical Intervention
Scenarios- Male
Remission Incidence RR Combined
Page | 41
Figure 12 Estimated Reduction in 12-Month Prevalence of ODD for Each of the Hypothetical Intervention Scenarios.
Table 11 and Table 12 provide the short-term and long-term impacts associated with each of the hypothetical scenarios as well as the impact of combining each scenario.
Relative to the baseline model, the short-term (2011-2021) impacts are expected to yield the following results:
By increasing remission by 10%, an estimated 2,000 fewer Canadian youth will be living with the effects associated with ODD by 2021 (a 0.08% reduction in 12-month prevalence relative to the baseline model);
By reducing all cause incidence by 10%, it is estimated that 7,940 fewer Canadian youth will be living with ODD by 2021 (a 0.35% reduction in 12-month prevalence relative to the baseline model);
Reducing the relative risk associated with a prior mental illness in childhood or adolescence by 10% has a negligible short-term impact; and
Page | 42 The combination of each of the above scenarios results in an estimated reduction of 9,790 Canadian youth living with ODD by 2021 (a 0.43% reduction in 12-month prevalence relative to the baseline model).
Relative to the baseline model, the long-term (2011-2041) impacts are expected to yield the following results:
By increasing remission by 10%, an estimated 2,380 fewer Canadian youth will be living with the effects associated with ODD by 2041 (a 0.08% reduction in 12-month prevalence relative to the baseline model);
By reducing all cause incidence by 10%, it is estimated that 9,640 fewer Canadian youth will be living with ODD by 2041 (a 0.37% reduction in 12-month prevalence relative to the baseline model);
Reducing the relative risk associated with a prior mental illness in childhood or adolescence has a negligible short-term impact; and
The combination of each of the above scenarios results in an estimated reduction of 11,800 Canadian youth living with ODD by 2041 (a 0.45% reduction in 12-month prevalence relative to the baseline model).
Table 11 Estimated Baseline and Reduction in Number of People Aged 9 to 19 Years with ODD (12-Month Prevalence) for the Baseline Model, and Each of the Hypothetical Intervention Scenarios.
Year Increase Remission Reduce Incidence
Reduce Relative Risk
Combined Intervention 2021 86,557 2,002 7,943 - 9,790 2031 94,535 2,299 9,302 - 11,380 2041 98,037 2,389 9,644 - 11,803 2021 49,123 1,144 4,505 - 5,562 2031 53,691 1,315 5,279 - 6,470 2041 55,679 1,367 5,473 - 6,710 2021 37,434 858 3,438 - 4,228 2031 40,844 984 4,023 - 4,910 2041 42,359 1,022 4,171 - 5,093
Baseline Number of People
Reduction in Number of People in each Scenario
Total
Male
Female
Impact of Different Intervention Scenarios on the Estimated Number of People with ODD (12-Month Prevalence) Aged 9 to 19 Years in Canada, by Scenario, 2011 to 2041
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Table 12 Estimated Baseline and Reduction in 12-Month Crude Prevalence of People Aged 9 to 19 Years with ODD for Each of the Hypothetical Intervention Scenarios.
Year Increase Remission Reduce Incidence
Reduce Relative Risk
Combined Intervention Total 2021 3.80% 0.08% 0.35% - 0.43%
2031 3.80% 0.08% 0.37% - 0.45%
2041 3.79% 0.08% 0.37% - 0.45%
Male 2021 4.20% 0.09% 0.39% - 0.47%
2031 4.20% 0.09% 0.41% - 0.50%
2041 4.20% 0.09% 0.41% - 0.50%
Female 2021 3.37% 0.07% 0.31% - 0.38%
2031 3.37% 0.07% 0.33% - 0.40%
2041 3.37% 0.07% 0.33% - 0.40%
Baseline 12-Month Prevalence
Reduction in 12-Month Prevalence Scenario
Reduction in Estimated 12-Month Prevalence of ODD in People Aged 9 to 19 Years in Canada, by Scenario, 2011 to 2041
Page | 44
2.1.4 CONDUCT DISORDERS
Figure 13 Estimated Number of People with Conduct Disorder (12-Month Prevalence) for the Baseline Model, and Each of the Hypothetical Intervention Scenarios.
Figure 13 Estimated Number of People with Conduct Disorder (12-Month Prevalence) for the Baseline Model, and Each of the Hypothetical Intervention Scenarios.