Cholinergic Deficits Found in Major Depression

Nicotinic cholinergic mechanisms in depression have been hypothesized for decades (Lancet 1972; 300:632), especially since increased risks for subsequent episodes were found in depressed patients who had stopped smoking (for a review, see Am J Psychiatry 1993; 150:546). Nevertheless, cholinergic mechanisms in depression have attracted relatively little research, unlike serotonergic and catecholaminergic mechanisms. These investigators used single-photon emission computed tomography to examine β₂-subunit-containing nicotinic acetylcholinergic receptors (β₂*-nAChRs) in 11 brain regions known to contain these receptors. Participants were 8 acutely ill and 15 recovered nonsmoking patients with major depression (age at onset, <25; medication-fre…