Comorbidity of Alcohol Use and Other Psychiatric Disorders and Suicide Mortality: Data from the South Korean National Health Insurance Cohort, 2002 to 2013

Abstract

Background: Previous studies have indicated that alcohol use disorder (AUD) and other psychiatric disorders increase the risk of suicide mortality. However, little research has investigated the concomitant effect of comorbid psychiatric disorders on suicide mortality. This study aimed to investigate the effect of comorbid AUD on suicide mortality of individuals with another psychiatric disorder using a national data sample.

Methods: We used the National Health Insurance Service-National Sample Cohort data from 2002 to 2013. We selected individuals with specific psychiatric disorders based on the International Classification of Diseases, 10th revision (F10-F48). Overall, the study included 741,601 participants. We utilized a prioritization process to identify the primary diagnosis for those with multiple diagnoses. All-cause mortality rates and suicide rates per 100,000 person-year (days) and the standardized mortality ratio (SMR) were calculated. Then, we compared the suicide-specific SMR of 3 different groups: (i) specific psychiatric disorder versus general public; (ii) specific psychiatric disorder comorbid with AUD versus general public; and (iii) specific psychiatric disorder comorbid with AUD versus specific psychiatric disorder without comorbid AUD.

Results: Patients with any specific psychiatric disorder showed higher suicide-specific SMR compared to the general population. Being comorbid with AUD further increased the risk of suicide among psychiatric patients. In particular, patients with bipolar affective disorders, organic mental disorders, or depressive disorders comorbid with AUD had about 2 to 4 times higher suicide-specific SMR compared to those without AUD (bipolar affective disorder: SMR = 3.01, 95% confidence interval (CI) [1.49, 4.54]; organic mental disorder: SMR = 3.43, 95% CI [1.05, 5.81]; depressive disorder: SMR = 2.06, 95% CI [1.52, 2.61]).

Conclusions: Our data indicate that having a psychiatric disorder increases the risk of committing suicide. More importantly, comorbid AUD further increases this risk of suicidal death for certain psychiatric disorders. This shows the importance of determining whether patients with psychiatric disorders have comorbid AUD to prevent suicide.

Keywords: Alcohol Use Disorder; Korea; National Health Insurance Service-National Sample Cohort; Psychiatric Comorbidity; Suicide.