The meta-chlorophenylpiperazine challenge test in cocaine addicts: hormonal and psychological responses.

We report on the neuroendocrine and psychological responsivity of 31 cocaine addicts and 14 controls to the serotonergic agonist, meta-chlorophenylpiperazine (m-CPP) (0.5 mg/kg p.o.). Cocaine addicts were subdivided into subjects with aggressive tendencies and other features similar to those found in type 2 alcoholics and subjects without these features. Following m-CPP, aggressive and nonaggressive patients had a significantly blunted prolactin response compared to controls, but there was no difference between the two patient subgroups. There was no difference between the cortisol responses of nonaggressive patients and controls, but aggressive patients had a significantly blunted cortisol response compared to controls and nonaggressive patients. Both patient subgroups reported more intense "activation-euphoria" and "high" responses following m-CPP than controls. These results could indicate the existence of alterations along serotonergic pathways in cocaine addicts taken as a group. In addition, a subgroup of patients who could be described as type 2 cocaine addicts appear to be biologically different from healthy subjects and from other cocaine addicts as indicated by a greater cortisol blunting following m-CPP.