Associations between lifetime mental disorders and suicidal behaviors: findings from the Taiwan psychiatry morbidity survey

Background: East Asia has high suicide rates but low prevalence of mental disorders. We examined the associations between prior lifetime mental disorders (mood disorders, anxiety disorders, substance use disorders, and impulse control disorders) and subsequent suicidal behaviors (suicidal ideation and attempts in the general population and suicide plans, planned attempts, and unplanned attempts in suicidal ideators) in Taiwan.

Methods: This survey applied the World Mental Health Survey Composite International Diagnostic Interview to a population representative sample of noninstitutionalized adults between 2003 and 2005. Odds ratios (ORs) obtained using discrete-time survival analysis were used to estimate population attributable fractions (PAFs) of suicidal behaviors due to lifetime mental disorders.

Results: Lifetime mental illness was a significant risk factor for subsequent suicidal behaviors (except unplanned attempts among ideators) despite the relatively low prevalence of mental disorders in people with suicidality (16.1%-35.0%). Each diagnosis increased the odds of suicidal ideation. In terms of acting on suicidal ideation, mood disorders were most strongly associated with having plans (OR = 10.0; 95% confidence interval, CI 4.3-21.1), whereas substance use disorders most strongly with either planned (OR = 27.3; 95% CI 6.3-118.5) or unplanned attempts (OR = 14.5; 95% CI 1.7-121.5). PAFs of all mental disorders on suicidality lay between 20 and 30% (except 11% of unplanned attempts among ideators). Mood, anxiety, and substance use disorders had higher PAFs than impulse control disorders.

Conclusions: In addition to mood disorders, considering anxiety and substance use disorders is essential in devising population-based suicide prevention strategies.