Study Examines Risk of Suicide and Mental Disorder Comorbidity among Male Veterans Using VA Healthcare
BACKGROUND:
Veterans who receive services at the Veterans Health Administration are at increased risk for suicide compared to the U.S. general population, and every year, more than 1,600 Veterans who use the VA healthcare system die by suicide. Mental disorders play a key role in suicide among VHA users. Moreover, mental disorder comorbidity is commonly present among individuals who die by suicide, generating interest in whether or not the potential risk conferred by two disorders in combination is greater than the sum of the risk conferred by each disorder considered separately. This retrospective study examined mental disorder comorbidity and suicide in a large national cohort of Veterans who use VA healthcare, particularly the association between differing two-way combinations of mental disorders and suicide risk. Using VA data, investigators identified 2,962,810 male Veterans who used VA healthcare in FY99 and were alive at the start of FY00. Veterans in this cohort were followed until death or the end of FY06. Six mental health disorders were measured separately and in combination: PTSD, substance use, depression, bipolar, anxiety, and schizophrenia.
FINDINGS:
- Among Veterans who died by suicide between FY00 and FY06 (n = 7,426, or 0.25% of the study cohort), 47% had been diagnosed with a mental disorder(s) including 19% with one mental disorder and 27% with two or more.
- Each mental disorder was associated with increased risk for suicide. However, nearly all two-way combinations of mental disorders showed a smaller increase in risk for suicide than would be expected by considering the risk associated with each disorder separately, which is interpreted to indicate sub-additive risk.
- Depression was the most common diagnosis among Veterans who died by suicide (31%), followed by substance use disorder (21%), anxiety disorder (15%), PTSD (12%), schizophrenia (9%), and bipolar disorder (9%).
- Authors note that sub-additive risk may be explained by factors that serve to reduce risk associated with a comorbid diagnosis such as common underlying causes of mental disorders, difficulties with differential diagnosis, and intensive clinical care and monitoring of patients with comorbidity.
LIMITATIONS:
- Mental disorder diagnoses were based on International Classification of Diseases, 9th Revision, diagnostic codes in administrative data with associated limitations of reliability and validity.
- Analyses could not ascertain the nature of relationships between mental disorders, e.g., disorders that may be primary vs. secondary to another diagnosis (i.e., substance-induced depression).
- Other comorbidities, including physical illnesses, were not analyzed.
AUTHOR/FUNDING INFORMATION:
Data for this study were acquired for program planning and evaluation purposes, and not for research. Drs. Conner, Bossarte, and Lu are part of VISN 2's Center of Excellence for Suicide Prevention, VAMC Canandaigua, NY. Drs. Bohnert, McCarthy, Valenstein, Ignacio, and Ilgen are part of HSR&D's Center for Clinical Management Research, Ann Arbor, MI.
Conner K, Bohnert A, McCarthy J, Valenstein M, Bossarte R, Ignacio R, Lu N, and Ilgen M. Mental Disorder Comorbidity and Suicide among 2.96 Million Men Receiving Care in the Veterans Health Administration Health System. Journal of Abnormal Psychology October 22, 2012;e-pub ahead of print.
