Faster cholinergic REM sleep induction in euthymic patients with primary affective illness.

Arecoline, a cholinergic muscarinic receptor agonist, induced rapid eye movement sleep significantly more rapidly in patients with primary affective illness in remission than in normal control subjects matched for age and sex. These results, and others, suggest that patients with primary affective illness may have a supersensitive cholinergic system both when they are ill and when their symptoms are in clinical remission.