Association of cocaine withdrawal symptoms with more severe dependence and enhanced subjective response to cocaine.

The purpose of this two part study was to better characterize cocaine users based on self-reported cocaine withdrawal symptoms by examining screening data and response to smoked cocaine in the human laboratory. The first study sample included male and female non-treatment seeking cocaine users who were screened as potential subjects for inpatient studies. Of the 555 subjects, 462 (82%) endorsed symptoms consistent with DSM-IV criteria for cocaine withdrawal. Cocaine users who met criteria for cocaine withdrawal, compared with those who did not, reported a significantly higher amount of cocaine use and a history of medical and psychosocial problems. Cocaine users meeting DSM-IV withdrawal criteria, which included endorsement of depression, were also more likely to have a history of depression, to have seriously considered suicide, and to have had chemical dependency treatment even when amount spent on cocaine was covaried. The second study sample, which was a subset of Study I, included those who participated in human cocaine studies following the phone screening. Cocaine users who met criteria for cocaine withdrawal (n=34), compared with those who did not (n=10), had enhanced subjective ratings of 'high' and 'feel the effect of last dose' in response to a single delivery of 0.4 mg/kg of smoked cocaine. These results suggest that history of cocaine withdrawal symptoms may be associated with enhanced cocaine responses and greater severity of cocaine dependence.