Early age of first sexual intercourse and affiliation with deviant peers predict development of SUD: a prospective longitudinal study.

OBJECTIVE A recent study has reported that early sexual behavior predicts the development of substance use disorders (SUD). However, that relationship was considered by its authors to be only tentative, because it was based on cross-sectional data rather than longitudinal data. Another recent study reported that deviant activities of peers predict development of SUD, although that relationship has not yet been confirmed. The objective of this study was to assess whether early onset of sexual intercourse and affiliation with deviant peers serve as predictors of the development of SUD, using a prospective longitudinal study design. METHOD We conducted a prospective longitudinal study of adolescents. These subjects were recruited at the age of 10-12years, with follow-up evaluations at ages 14, 16, 19, 22, and 25. The sample included 136 male subjects. Cox regression analyses were performed, with age of first intercourse, neurobehavioral disinhibition, exposure to drugs in the neighborhood, and deviant activities of peers as factors in the analyses. RESULTS Earlier age at first intercourse and deviant activities of peers each predicted a significantly higher risk of subsequently developing a SUD (Wald=8.3, df=1, p=0.004; Wald=7.5, df=1, p=0.006, respectively). CONCLUSIONS The results of this study confirm that early onset of sexual intercourse and affiliation with deviant peers predict the early development of substance use disorders, using a prospective longitudinal study design.