Military service branch differences in alcohol use, tobacco use, prescription drug misuse, and mental health conditions.

Introduction: Rates of substance use and mental health conditions vary across military service branches, yet branches also differ notably in terms of demographics and deployment experiences. This study examines whether branch differences in substance use and mental health outcomes persist after adjustment for a comprehensive set of demographic and deployment-related factors.

Methods: Data on 16,699 Armed Forces Active Duty service members were from the 2015 Department of Defense Health Related Behaviors Survey. Service branch-specific prevalences were estimated for self-reports of heavy episodic drinking (HED), possible alcohol use disorder (AUD), current smoking, e-cigarette use, smokeless tobacco use, prescription drug misuse, probable post-traumatic stress disorder (PTSD), probable depression, and probable anxiety. Using logistic regression, we assessed whether branch differences persisted after adjusting for an extensive array of demographic factors (among full sample) and deployment/combat factors (among ever-deployed subgroup).

Results: HED, AUD, smoking, e-cigarette use, smokeless tobacco use, depression, and anxiety were highest in the Marine Corps; prescription drug misuse and PTSD were highest in the Army. HED, AUD, smoking, smokeless tobacco use, PTSD, depression, and anxiety were lowest in the Air Force; e-cigarette use and prescription drug misuse were lowest in the Coast Guard. Demographics and deployment/combat experiences differed across branches. After adjustment, service members in the Army, Marine Corps and Navy exhibited nearly 2-3 times the odds of multiple mental health conditions and substance use behaviors relative to the Air Force.

Conclusion: Service branch differences were not fully explained by variation in demographics and deployment/combat experiences.