Serum prolactin levels during extended cocaine abstinence.

Following a report indicating almost a 100% risk for hyperprolactinemia in cocaine users after 1 month of abstinence, the authors determined the serum prolactin concentrations of 23 male inpatients who had abstained from cocaine for 2-43 weeks. None showed high prolactin levels; this places the incidence below 12.3% with 95% confidence. These results imply that persistent hyperprolactinemia requires a medical explanation other than cocaine abstinence itself.