Slow wave sleep and 5-HT2 receptor sensitivity during maintenance tricyclic antidepressant treatment.

The 5-HT2 receptor antagonist cyproheptadine significantly increased slow wave sleep in 12 healthy control subjects but not in 12 patients with a history of major depression, maintained on tricyclic antidepressant treatment. Cyproheptadine produced a similar reduction in REM sleep in both groups of subjects. The results are consistent with the hypothesis that tricyclic antidepressant treatment alters brain 5-HT2 receptor sensitivity, but a primary abnormality in slow wave sleep regulation in depressed patients cannot be excluded.