Differences in Co-occurring Disorder Timing, Onset, and Sequence by Gender

This study models co-occurring disorder (COD) onset and disorder sequence, using time-to-event data, to understand these trends and how they differ by gender. We conducted survival analyses using the National Epidemiologic Survey of Alcohol and Related Conditions-III: a cross-sectional, nationally representative dataset of the US population in 2014–2015. Cox proportional hazard models estimated the impact of disorder sequence on lifetime hazard of COD. Gender differences in the role of disorder sequence were tested using a product interaction term. Most people who developed COD had a psychiatric disorder before a substance use disorder. Younger age, being US-born, being non-Hispanic White, having family history of disorder, and childhood adversity were all associated with increased risk and faster development of COD. A gender interaction was present with disorder sequence having large and opposite associations with lifetime COD for men and women. Risk of co-occurrence for men was higher than women if they experienced psychiatric disorder while risk of co-occurrence for women was higher than men who had substance use disorder. Attending to gender differences in COD research is critical and providing tailored resources, treatment, and support for men and women may be warranted.