Are trait impulsivity and exposure to cannabis or alcohol associated with the age of trajectory of cocaine use? A gender-specific dimensional analysis in humans with cocaine dependence diagnosis

Cocaine use disorders (CUD) cause major morbidity and optimized prevention efforts are critical. It is unclear if trait impulsivity and exposure to cannabis or alcohol are associated with age trajectory of cocaine use (e.g., age of onset of heaviest use, or time of escalation), or with vulnerability to develop a CUD. This is an observational study with volunteers (≤ 18 years old), from a metropolitan area. The sample (n = 1,010) included: n = 360 normal volunteers, n = 438 with cocaine dependence (CD) diagnoses, and n = 212 with other addictive diseases. Trait impulsivity was examined with BIS-11 scores. Maximal self-exposure to cannabis, alcohol, and cocaine were characterized dimensionally with Kreek-McHugh-Schluger-Kellogg (KMSK) scales. Time of escalation was defined as the interval between age of first use and age of onset of heaviest use. Onset of maximal use of cannabis (median age = 17) and alcohol (median age = 21) preceded that of cocaine (median age = 27), in volunteers with CD. Multivariate Cox regressions in volunteers with CD show that increasing self-exposure to cannabis was a predictor of earlier onset of heaviest use of cocaine. Also, more rapid time of escalation of alcohol was a predictor of more rapid time of escalation of cocaine. A multiple logistic regression shows that increasing self-exposure to cannabis or alcohol was a positive predictor of odds of CD diagnosis. Trait impulsivity and gender were not significant predictors in these multivariate analyses. This study shows that aspects of adolescent exposure to nonmedical cannabis and alcohol are predictors of early onset of CUD, and may be potentially targeted for prevention efforts.