The influence of partner drug use and relationship power on treatment engagement.

Substance-using intimate partners negatively influence individuals' substance abuse treatment engagement and drug use, but little else is known about effects of intimate relationships on treatment. We examine how relationship dynamics (power, control, dependence, insecurity and decision-making power) influence treatment engagement, and whether this differs by gender and partner drug use. Sixty-four heroin users (42 men, 22 women) receiving methadone detoxification treatment in Los Angeles were interviewed at treatment entry and submitted daily diaries of drug use throughout the 21-day treatment. Total number of reported heroin-free days in the first eight treatment days was the dependent variable. Bivariate analyses revealed, that compared to men, women were more likely to have substance-using partners, reported greater power over a partner and greater household decision-making power in their relationships. Multivariate analysis indicated that individuals whose partners had more control over them reported fewer days abstinent. Among individuals with heroin-using partners, greater household decision-making power was associated with more days abstinent, but there was no association for individuals with non-using partners. Relationship power dynamics may be important influences on the treatment process, and some dimensions of power may interact with partner drug use status.