Multiple Mental Disorders and Suicidality; Cross-Ethnic Variation among Blacks

For psychiatric disorders, comorbidity is a rule rather than exception. Thus it is particularly important to study additive and multiplicative effects of multiple mental disorders on suicidal behaviors.
The aim of this study was to investigate the ethnic differences in multiplicative effects of mental disorders on suicidal ideation among Black adults in the United States.
Data came from the National Survey of American Life, 2001-2003. For this study, we used data of 5,181 Black adults (3,570 African Americans and 1,621 Caribbean Blacks). Lifetime depression, anxiety, and drug abuse as well as suicidal ideation were measured, using the World Mental Health Composite International Diagnostic Interview (WMH-CIDI). Ethnic specific logistic regressions were used to determine multiplicative effects of anxiety, depression and drug abuse on suicidal thoughts among African Americans and Caribbean Blacks.
Depression showed multiplicative effects with anxiety and drug abuse for African Americans, but not Caribbean Blacks. Drug abuse and anxiety showed multiplicative effects among Caribbean Blacks but not African Americans.
Based on our study, ethnicity modifies how anxiety, depression and drug abuse contribute to suicidality among Blacks. As suicide risk is differently influenced by multiple psychiatric disorders for African Americans and Caribbean Blacks, ethnic-specific programs for screening and prevention of suicide is suggested.