Classifying psychotropic drugs by mode of action and not by target disorder.

1. Agents called ‘‘antidepressants’’ also treat multiple anxiety disorders such as generalized anxiety disorder, posttraumatic stress disorder, panic disorder, and social anxiety disorder; impulsive/compulsive spectrum disorders, such as obsessive compulsive disorder; eating disorders, such as bulimia; and pain conditions, such as neuropathic pain. Agents called ‘‘antipsychotics’’ are also proven to have efficacy in unipolar treatmentresistant depression, in acute bipolar mania, and in bipolar depression. 2. Rather than classifying psychotropic drugs by therapeutic target(s), a paradigm shift is afoot to classify drugs by their known and most potent pharmacologic mode(s) of actions. 3. There are 5 known modes of action of psychotropic drugs: