Prevalence of Central Nervous System Polypharmacy and Associations with Overdose and Suicide-Related Behaviors in Iraq and Afghanistan War Veterans in VA Care 2010–2011

BACKGROUND The increase in the quantities of central nervous system (CNS)-acting medications prescribed has coincided with increases in overdose mortality, suicide-related behaviors, and unintentional deaths in military personnel deployed in support of the wars in Iraq and Afghanistan. Data on the extent and impact of prescribing multiple CNS drugs among Iraq and Afghanistan Veterans (IAVs) are sparse. OBJECTIVES We sought to identify the characteristics of IAVs with CNS polypharmacy and examine the association of CNS polypharmacy with drug overdose and suicide-related behaviors controlling for known risk factors. METHODS This cross-sectional cohort study examined national data of Iraq and Afghanistan Veterans (N = 311,400) who used the Veterans Health Administration (VHA) during the fiscal year 2011. CNS polypharmacy was defined as five or more CNS-acting medications; drug/alcohol overdose and suicide-related behaviors were identified using ICD-9-CM codes. Demographic and clinical characteristics associated with CNS polypharmacy were identified using a multivariable logistic regression model. RESULTS We found that 25,546 (8.4 %) of Iraq and Afghanistan Veterans had CNS polypharmacy. Those with only post-traumatic stress disorder (PTSD) (adjusted odds ratio (AOR) 6.50, 99 % confidence interval (CI) 5.96-7.10), only depression (AOR 6.42, 99 % CI 5.86-7.04), co-morbid PTSD and depression (AOR 12.98, 99 % CI 11.97-14.07), and co-morbid traumatic brain injury (TBI), PTSD, and depression (AOR 15.30, 99 % CI 14.00-16.73) had the highest odds of CNS polypharmacy. After controlling for these co-morbid conditions, CNS polypharmacy was significantly associated with drug/alcohol overdose and suicide-related behavior. CONCLUSION CNS polypharmacy was most strongly associated with PTSD, depression, and TBI, and independently associated with overdose and suicide-related behavior after controlling for known risk factors. These findings suggest that CNS polypharmacy may be used as an indicator of risk for adverse outcomes. Further research should evaluate whether CNS polypharmacy may be used as a trigger for evaluation of the current care provided to these individuals.