Abstract
Rationale
Serotonergic (5‐HT) mechanisms appear to mediate central effects of cocaine. Therefore 5‐HT disturbances could be associated with drug severity.
Objectives
We investigated whether prolactin (PRL) response to meta‐chlorophenylpiperazine (m‐CPP), a mixed 5‐HT agonist/antagonist were associated with severity of cocaine use.
Methods
Thirty‐six cocaine‐dependent subjects and 33 controls underwent a challenge with 0.5 mg/kg of oral m‐CPP. Severity of drug use was assessed using the Addiction Severity Index (ASI).
Results
The PRL response to m‐CPP was significantly blunted in cocaine patients compared to controls (F= 21.86, p < 0.001). ΔPRL (peak PRL—baseline PRL) was negatively correlated with ASI‐drug (r = −0.45, p < 0.01), ASI‐alcohol (r = −0.32, p < 0.05), and ASI‐psychological (r = −0.41, p < 0.01) composite scores, and with the quantity, frequency and duration of drug use (r ranged from − 0.41 to − 0.32, p ranged from < 0.01 to 0.05). Hierarchical regressions showed that ASI‐drug composite scores significantly predicted the variance in ΔPRL after controlling for behavioral and demographic variables (F = 4.27, p < 0.05).
Conclusions
The results indicate that disturbances in 5‐HT function as reflected by a blunted response to m‐CPP seem to be primarily associated with severity of drug use and to a lesser, although significant extent with behavioral traits in cocaine‐dependent patients. Copyright © 2006 John Wiley & Sons, Ltd.