ACHE and major depressive disorder: Increasing brain acetylcholine levels by another acetylcholinesterase inhibitor, physostigmine, triggers anxiety, and depression in control human subjects and in patients with mood disorders (Janowsky and Overstreet 1990; Risch et al. 1980), whereas blocking acetylcholinesterase activity induces depression/anxiety‐like behavior and social stress in rodents as well, and these effects can be reversed by blocking cholinergic receptors (Mineur et al. 2013).