Seasonal variation in the dexamethasone suppression test: a longitudinal study in chronic schizophrenics and in healthy subjects.
To evaluate seasonal influences on the dexamethasone suppression test (DST), cortisol and melatonin responses to dexamethasone were assessed in drug-treated chronic schizophrenics and in drug-free healthy volunteers in different seasons of the year, according to a longitudinal study design. In schizophrenic patients, there was a greater rate of cortisol non-suppression to DST in February as compared to November and May (chi 2 = 4.5, p = 0.03) with no significant differences in pre- and post-dexamethasone plasma cortisol levels. In healthy volunteers, in contrast, no seasonal variation in DST results was observed. Moreover, dexamethasone administration did not significantly affect morning plasma melatonin levels in either patients or healthy controls. These findings suggest that seasonality may be of critical importance in evaluating DST results in schizophrenic patients, but not in healthy subjects.
Monteleone
P
P
Institute of Psychiatry, School of Medicine, Second University of Naples, Italy.
Piccolo
A
A
Martino
M
M
Maj
M
M
D000328:Adult; D014151:Anti-Anxiety Agents / Q000627:therapeutic use; D014150:Antipsychotic Agents / Q000627:therapeutic use; D001569:Benzodiazepines; D002908:Chronic Disease; D003907:Dexamethasone; D005260:Female; D006220:Haloperidol / Q000031:analogs & derivatives / Q000627:therapeutic use; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D008137:Longitudinal Studies; D008297:Male; D008550:Melatonin / Q000097:blood*; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D011863:Radioimmunoassay; D012016:Reference Values; D012559:Schizophrenia / Q000097:blood / Q000175:diagnosis* / Q000188:drug therapy; D012565:Schizophrenic Psychology; D012621:Seasons
D014151:Anti-Anxiety Agents; D014150:Antipsychotic Agents; D001569:Benzodiazepines; D003907:Dexamethasone; C033563:haloperidol decanoate; D006220:Haloperidol; D008550:Melatonin; D006854:Hydrocortisone