Romantic relationship status changes and substance use among 18- to 20-year-olds.

<bold>Objective: </bold>Changes in romantic relationship status are common in emerging adulthood and may be linked to changes in substance use. This study tested the hypothesis that entry into relationships or transitioning to a more committed status leads to decreases in substance use and that dissolution of relationships or transitioning to a less committed status results in increases in substance use.<bold>Method: </bold>Data were from a community sample of 939 individuals. Substance use (heavy drinking, marijuana use, and cigarette smoking) and relationship status (single, in a romantic relationship but not cohabiting, cohabiting, or married) were assessed at the beginning and end of three 6-month intervals between the ages of 18 and 20 years. Models were estimated to assess the association between transitions in relationship status and substance use, adjusting for prior levels of use.<bold>Results: </bold>There were increases in heavy drinking, marijuana use, and cigarette smoking associated with dissolution of a romantic relationship, as well as increases in marijuana use and cigarette smoking associated with switching partners within a 6-month interval. Mediation analyses found some support for increases in both depressive symptoms and exposure to substance-using peers partially accounting for these associations. Decreases in substance use were not found for individuals entering into a new relationship or transitioning to a more committed relationship status. In fact, cigarette smoking increased among those who went from being single to being in a romantic relationship compared with those whose relationship status did not change.<bold>Conclusions: </bold>Emerging adults who experience dissolution of romantic relationships or quickly move from one relationship to another experience increased substance use. Both depressive symptoms and changes in peer environments may partially account for these changes in use. [ABSTRACT FROM AUTHOR]