Familiality of Addiction and Its Developmental Mechanisms in Girls

Introduction. Drug addictions (drug use disorders, DUD) have been theorized to share mechanisms of risk variation with other consummatory behaviors. These mechanisms, having deep evolutionary roots, may originate from many levels of biological organization – from genetic to biochemical and physiological to psychological, and can vary across sexes. We have previously shown that the familiality of addiction to illicit drugs (parental DUD) is related to the rate of sexual maturation in male offspring, which in turn is associated with their disruptive behavior, peer delinquency, and risk for DUD.

In this study, we hypothesized that common mechanisms exist for familial risk for DUD, physiological maturation and nutritional status in girls. Whereas body fat content must exceed a threshold to enable adrenarche and gonadarche, nutritional status may also be a behavior risk indicator. In particular, impaired psychological self-regulation associated with (and likely to a degree underlying) DUD risk may manifest in early-onset overeating, which could in turn increase the rate of reproductive maturation resulting in a greater likelihood of affiliation with deviant/older peers and drug use.

Methods. The sample consisted of 255 families ascertained through the father who either had (N=95) or did not have (N=130) a substance use disorder related to an illicit drug(s), and who had a 10-12 year old daughter and her biological mother available for study (20% of whom were also affected with a DUD). The girls are prospectively assessed at regular intervals until age 30, and at the time of this study ranged 14-30 (mean ± SEM=25.7 ± 0.20). Survival analysis (Cox proportional hazard regression) and structural equation modeling were used to evaluate the relationships between parental DUD (number of affected parents, NAP), nutritional status (subscapular skinfold measurements), sexual maturation (Tanner stage by pubic hair), peer delinquency, and the daughter’s lifetime DUD diagnosis.

Results. In survival analysis, NAP was significantly positively related to the rate of sexual maturation in girls. Path analysis of the data from three consecutive assessments (ages 10-12, 14 and 16) is consistent with mediation of the relationship between NAP and peer delinquency (PD) by sexual maturation, whereas the relationship between NAP and sexual maturation is mediated by the fat content. A significant indirect effect of sexual maturation stage at the early age of 10-12 on the girls' DUD risk is mediated by peer delinquency.

Conclusions. The data are consistent with the hypothesis that the intergenerational transmissibility of the DUD risk in females is mediated by elevated nutrition, leading to an increased rate of sexual maturation and affiliation with deviant peers.