The increase in slow wave sleep which followed administration of the 5-HT2 receptor antagonist, ritanserin, was not significantly different between a group of 12 recovered, drug free depressed patients and a group of 12 health matched controls. The results suggests that there is no underlying abnormality in the 5-HT2 receptor regulation of slow wave sleep in recovered depressives, and that abnormalities in this measure reported previously in such patients may have been caused by use of concomitant tricyclic antidepressant medication. The baseline sleep parameters did not differ between recovered depressives and controls with the exception of stage 1 sleep, which was increased in the patient group.