Longitudinal Associations From Neurobehavioral Disinhibition to Adolescent Risky Sexual Behavior in Boys: Direct and Mediated Effects Through Heavy Alcohol Consumption

Introduction: Risky sexual behavior and alcohol misuse among youth remain significant public health concerns. One-third of all high school students report having engaged in sexual intercourse within the past three months and 14% admit to at least four sexual partners during their lifetime. Twenty-two percent of all high school students report having had five or more drinks of alcohol in a row within the past month. Determining which risk factors contribute to liability for both alcohol use and risky sex would identify characteristics which, if ameliorated through prevention, could mitigate multiple behavior problems. It was hypothesized that heavy alcohol use, but not frequency of alcohol use, would mediate longitudinal relationships between neuro-behavioral disinhibition (ND) (i.e., low inhibitory regulation) at age 11.3 and number of sexual partners at age 16.1.

Methods: Participants were 411 adolescent boys. ND was measured as a composite score with affective, behavioral, and cognitive indicators. Quantity and frequency of alcohol use were assessed using a modified version of the Lifetime History of Alcohol Use survey. A single item from the survey of risky sexual behavior was taken from the Pittsburgh Youth Study to measure the number of sexual partners in the past year. General linear models were used to test mediation and the Sobel test was used to estimate the indirect effect of the mediator.

Results: As hypothesized, ND at age 11.3 years of age was significantly related to quantity of alcohol use on a typical drinking occasion at 13.4 and number of sexual partners at 16.1 years of age. In addition, quantity of alcohol consumed mediated the relation between ND and number of sexual partners (Sobel test = 2.13, SE = 0.002, p < 0.05). Frequency of alcohol use did not significantly mediate the direct effect of ND on number of sexual partners. 

Conclusions: Findings indicate that the number of sexual partners in mid-adolescence is predicted by individual differences in boys’ ND during childhood and heavy alcohol consumption in early adolescence (but not frequency of alcohol consumption). Findings suggest that ND may be a potential target for multi-outcome health interventions. Intervention strategies may include screening youth with poor psychological self-regulation into selective interventions based on pre-existing levels of ND. Alternatively, or perhaps in tandem with selective interventions, universal prevention programs that target all youth may focus on promoting ND as a predictor of later alcohol misuse and risky sex.