• Clonidine hydrochloride, administered intravenously (2 μg/kg) during the second non—rapid eye movement period, was significantly less suppressant of rapid eye movement sleep in 10 depressed patients with primary major affective illness, according to Research Diagnostic Criteria, than in three groups of matched subjects (10 normal controls, 10 patients with minor depression, and 10 patients with generalized anxiety). These results suggest that depressed patients with major primary affective illness have downregulated α2-adrenergic receptors. These findings are consistent with the cholinergic-aminergic balance hypothesis of depression and support the aminergic side of the concept. Finally, the rapid eye movement sleep response to clonidine could provide a new biological marker of affective illness.
Schittecatte M, Charles G, Machowski R, Garcia-Valentin J, Mendlewicz J, Wilmotte J. Reduced Clonidine Rapid Eye Movement Sleep Suppression in Patients With Primary Major Affective Illness. Arch Gen Psychiatry. 1992;49(8):637-642. doi:10.1001/archpsyc.1992.01820080045007