Alcohol and cocaine are frequently used together. Little is known about which factors are related with the development of either cocaine or alcohol dependence in dually users.

To determine variables associated with the risk fro the development of either cocaine or alcohol dependence in non-dependent drinkers with recreational cocaine use during a 4 year-follow-up period.

A prospective cohort study was performed to establish the risk factors associated with alcohol and cocaine dependence. Subjects recruited (N=336), from primary care centres. At baseline were classified as heavy drinkers and cocaine users (HD+Co, N=227) and alcohol abusers with cocaine use (AA+Co, N= 109).

At 4-year follow-up assessment, AA+Co subjects had higher rates of prevalence for cocaine (55% vs. 32%, p<0.001)) and alcohol dependence (97.5% vs. 58.2%, p<0.001) than HD+Co participants. Being alcohol abuser and single were eight and three times, respectively, more likely to develop cocaine dependence. When impulse control disorders or alcohol abuse occurred the odds ratio of developing alcohol dependence was 9 and 5.7 respectively. Also, alcohol abuse at baseline was associated with shortened time between onset of abuse and dependence for cocaine use disorders and for alcohol use disorders.

Alcohol abuse in heavy drinkers with recreational cocaine use predicted alcohol and cocaine dependence at follow-up. Our findings agree with previous findings supporting the relationship between impulsivity and risk for substance use disorders.