Clinical neuropsychology requires an in-depth knowledge of&colon; neuroanatomy, neurobiology, psychopharmacology and neuropathology. Stephen Michael Stahl is an author and professor of psychiatry with expertise in psychopharmacology. This extended period involves comprehensive training in psychiatric diagnosis, psychopharmacology, medical care issues, and psychotherapies. In psychopharmacology, GABA receptor PAMs used as drugs have mainly sedative and anxiolytic effects. Psychopharmacology is the study of drug-induced mental effects. In the early stages, psychopharmacology was primarily used for sedation. Siegel is the author of several noted studies and books on psychopharmacology, hallucination, and paranoia. This knowledge has been gained using imaging techniques, psychopharmacology, neuroimmunochemistry and so on. Until 2009, he was a professor at the University of Bristol heading their Psychopharmacology Unit. In the 1950s, major breakthrough in psychopharmacology occurred around the world. The TCAs were developed amid the "explosive birth" of psychopharmacology in the early 1950s. The term "psychopharmacology" was probably first coined by David Macht in 1920. He is a former Secretary of the British Association for Psychopharmacology.