BEHAVIORAL-RESPONSES TO INTRAVENOUS META-CHLOROPHENYLPIPERAZINE IN PATIENTS WITH SEASONAL AFFECTIVE-DISORDER AND CONTROL SUBJECTS BEFORE AND AFTER PHOTOTHERAPY

A comparison of the baseline and post-infusion effects of the serotoni n agonist meta-chlorophenylpiperazine (m-CPP) in 10 patients with seas onal affective disorder (SAD) and 11 healthy control subjects revealed significantly different subjective response profiles between the grou ps. Several baseline and m-CPP-stimulated responses in symptoms putati vely related to serotonergic function changed significantly after a we ek's exposure to phototherapy in the SAD patients but not the control subjects. Before phototherapy, depressed patients with SAD reported ac tivation-euphoria responses to m-CPP and significant decreases in carb ohydrate hunger, but insignificant changes in feeling slowed or sleepy , while control subjects reported no mood or appetite changes but sign ificant increases in feeling slowed down following m-CPP. After photot herapy, which led to a significant reduction in baseline depressive sy mptom ratings to near-euthymic levels in the SAD patients, almost all of the patients' responses to m-CPP were normalized and no longer diff ered from the control subjects' responses. These results provide evide nce of a possible dysregulation in serotonergic neurotransmission in d epressed SAD patients that normalizes following treatment with phototh erapy.