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

•Study population include 16,699 active duty service members in U.S. military.•We test for differences across service branch in substance use and mental health outcomes.•The Air Force had the lowest rates of nearly all substance use and mental health outcomes.•Many outcomes were 2–3 times higher among Army, Marine Corps and Navy, after adjustment.•Differences are not fully explained by branch differences in deployment/combat experiences.