Synergistic Effects of Lifetime Psychiatric Disorders on Suicidal Ideation Among Blacks in the USA

Abstract

In this study, we aimed to investigate the synergistic effects of lifetime psychiatric disorders including general anxiety disorder (GAD), major depressive disorder (MDD), and drug abuse disorder (DAD) on serious suicidal thoughts among a nationally representative sample of Blacks in the USA. For this study, we used data of 5,181 Black (3,570 African-American and 1,621 Caribbean Black) adults who participated in the National Survey of American Life (NSAL), 2001–2003. Three lifetime psychiatric disorders (i.e., MDD, GAD, and DAD) were considered as independent variables. Lifetime serious suicidal ideation was considered as the dependent variable. Age, gender, ethnicity, education, employment, marital status, and region were control variables. Logistic regression was used to determine separate, additive, and synergistic effects of GAD, MDD, and DAD on serious suicidal thoughts. Individuals with comorbid GAD and MDD [odds ratio (OR) = 3.61, 95 % confidence interval (CI) = 1.26–10.33], GAD and DAD (OR = 3.22, 95 % CI = 1.05–9.85), and MDD and DAD (OR = 2.25, 95 % CI = 1.16–4.35) were at highest risk of suicidal ideation. In the absence of GAD and MDD, DAD was associated with higher odds of suicidal ideation (OR = 3.55, 95 % CI = 2.15–5.87); however, in the absence of DAD, neither GAD nor MDD was associated with suicidal ideation. Gender also modified the synergistic effects of GAD, MDD, and DAD on suicidal ideation. Based on our study, GAD, MDD, and DAD have synergistic effects on suicidal thoughts among Blacks. Results may have implications for the reduction of suicide due to psychiatric disorders among Blacks.