Partner Effects: Analyzing Service Member and Spouse Drinking Over Time.

Introduction: Excessive alcohol use is a significant problem in the military. Although there is a growing emphasis on family-centered alcohol prevention approaches, little is known about the interplay between partners' drinking behaviors. This study examines how service members and their spouses influence each other's drinking behavior over time and explores the complex individual, interpersonal, and organizational factors that may contribute to alcohol use.

Methods: A sample of 3,200 couples from the Millennium Cohort Family Study was surveyed at baseline (2011-2013) and follow-up (2014-2016). The research team estimated how much partners' drinking behaviors influenced one another from baseline to follow-up using a longitudinal structural equation modeling approach. Data analyses were conducted in 2021 and 2022.

Results: Drinking patterns converged between spouses from baseline to follow-up. Participants' own baseline drinking had a small but significant effect on changes in their partners' drinking from baseline to follow-up. Results from a Monte Carlo simulation showed that the longitudinal model could reliably estimate this partner effect in the presence of several potential sources of bias, including partner selection. The model also identified several common risk and protective factors for drinking shared by both service members and their spouses.

Conclusions: Findings suggest that changing the drinking habits of one spouse could lead to a change in the drinking habits of the other, which supports family-centered alcohol prevention approaches in the military. Dual-military couples especially may benefit from targeted interventions because they face a higher risk of unhealthy alcohol consumption.