Rationale: Alteration in serum prolactin (PRL) levels may reflect changes in central dopamine activity, which modulates the behavioral effects of cocaine. Therefore, serum PRL may have a potential role as a biological marker of drug severity and treatment outcome in cocaine dependence.
Objective: We investigated whether serum PRL levels differed between cocaine-dependent (CD) subjects and controls, and whether PRL levels were associated with severity of drug use and treatment outcome in CD subjects.
Methods: Basal PRL concentrations were assayed in 141 African-American (AA) CD patients attending an outpatient treatment program and 60 AA controls. Severity of drug use was assessed using the Addiction Severity Index (ASI). Measures of abstinence and retention during 12 weeks of treatment and at 6-month follow-up were employed as outcome variables.
Results: The basal PRL (ng/ml) in CD patients (9.28+/-4.13) was significantly higher than controls (7.33+/-2.94) (t=3.77, P<0.01). At baseline, PRL was positively correlated with ASI-drug (r=0.38, P<0.01), ASI-alcohol (r=0.19, P<0.05), and ASI-psychological (r=0.25, P<0.01) composite scores, and with the quantity of cocaine use (r=0.18, P<0.05). However, PRL levels were not significantly associated with number of negative urine screens, days in treatment, number of sessions attended, dropout rate or changes in ASI scores during treatment and at follow-up. Also, basal PRL did not significantly contribute toward the variance in predicting any of the outcome measures.
Conclusion: Although cocaine use seems to influence PRL levels, it does not appear that PRL is a predictor of treatment outcome in cocaine dependence.