Alcohol and Cannabis Use Within Emerging Adults' Committed Romantic Relationships: Associations with Relationship Functioning and Quality of Life.

This study examines alcohol and cannabis use within emerging adults' committed romantic relationships and its association with relationship functioning (satisfaction, stability) and well-being (life satisfaction, anxiety, depression). Participants completed surveys in 2020 and 2021 (N=1,214). Latent profile analysis identified four classes of couples' substance use patterns: concordant (similar) infrequent use (81.9% of sample), near-daily partner cannabis use (6.0%), near-daily respondent cannabis use (6.5%), and concordant moderate alcohol and near-daily cannabis use (5.5%). Cross-sectionally, respondents who reported concordant infrequent use had significantly higher well-being than those who reported concordant heavier use; there were no class differences involving the two types of discordant couples. In general, class membership did not predict changes in well-being or relationship functioning over a one-year period. Results provide new insights into patterns of both alcohol and cannabis use within committed romantic relationships of emerging adults that may have implications for well-being during this developmental period.