Background: Numerous studies have documented higher substance use rates among bisexual than heterosexual young women, although little is known about the developmental factors contributing to these differences. Based on self-reported sexual orientation collected at age 23, this study identified similarities and differences between bisexual and heterosexual women in their substance use at ages 14 and 18, compared these groups at ages 14 and 18 on key psychosocial factors known to predict young adult substance use, and determined whether these psychosocial factors at age 18 could account for sexual orientation differences in substance use at age 23.
Methods: Longitudinal survey data from a West Coast cohort were used to compare heterosexual (n = 1,479) and bisexual (n = 141) women on their substance use and psychosocial characteristics.
Results: During adolescence, bisexual women were more likely to have been current and solitary substance users; reported stronger pro-drug beliefs and lower resistance self-efficacy; perceived greater parental approval of their substance use; had more exposure to substance-using peers; and reported poorer mental health. By age 23, bisexual women had higher rates of current substance use, greater quantity and frequency of use, and more problematic alcohol and drug use. Differences in problematic use at age 23 could be partially explained by risk factors assessed five years earlier at age 18, particularly pro-drug social influences and beliefs.
Conclusions: Notwithstanding the lack of longitudinal data on sexual orientation, these results provide important insights regarding the drug prevention needs of bisexual women.