Abstract
Introduction: Epidemiological studies indicate that individuals with one type of mental disorder have an increased risk subsequently of developing other types of mental disorders. The aim of this study was to undertake a comprehensive analysis of pairwise lifetime comorbidity across a range of common mental disorders based on a diverse range of population-based surveys.
Methods: The WHO World Mental Health (WMH) surveys assessed 145,990 adult respondents from 27 countries. Based on retrospectively-reported age-of-onset for 24 DSM-IV mental disorders, associations were examined between all 276 logically possible temporally-ordered disorder pairs. Overall and time-lagged hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards models. Absolute risks were estimated using competing risks survival analyses. Estimates were generated separately for men and women.
Results: Each prior lifetime mental disorder was associated with an increased risk of subsequent first onset of each other disorder. The HRs were largest for closely-related types of disorders (e.g. prior Major Depressive episode and later Dysthymia HR = 60.5, 95%CI 55.1-66.4) and were most prominent in the first 1-2 years after onset of the temporally primary prior disorder. Although HRs declined with time, significantly elevated risk of subsequent comorbidity persisted for at least 15 years. Appreciable absolute risks of secondary disorders were found over time for many pairs.
Discussion: Survey data from a range of sites confirms that comorbidity between mental disorders is common. Understanding risks of temporally secondary disorders may help design practical programs for primary prevention of secondary disorders.
Methods: The WHO World Mental Health (WMH) surveys assessed 145,990 adult respondents from 27 countries. Based on retrospectively-reported age-of-onset for 24 DSM-IV mental disorders, associations were examined between all 276 logically possible temporally-ordered disorder pairs. Overall and time-lagged hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards models. Absolute risks were estimated using competing risks survival analyses. Estimates were generated separately for men and women.
Results: Each prior lifetime mental disorder was associated with an increased risk of subsequent first onset of each other disorder. The HRs were largest for closely-related types of disorders (e.g. prior Major Depressive episode and later Dysthymia HR = 60.5, 95%CI 55.1-66.4) and were most prominent in the first 1-2 years after onset of the temporally primary prior disorder. Although HRs declined with time, significantly elevated risk of subsequent comorbidity persisted for at least 15 years. Appreciable absolute risks of secondary disorders were found over time for many pairs.
Discussion: Survey data from a range of sites confirms that comorbidity between mental disorders is common. Understanding risks of temporally secondary disorders may help design practical programs for primary prevention of secondary disorders.
| Original language | English |
|---|---|
| Journal | Epidemiology and Psychiatric Sciences |
| Publication status | Accepted/In press - 3 Jul 2020 |
