Contributors: Andrew White MD & Travis Barlock MD In this episode of Mental Health Monthly, Dr. Andrew White, a practicing psychiatrist with an addiction medicine fellowship, and Dr. Travis Barlock, an emergency physician at Swedish Medical Center, discuss the various presentations and etiologies of acute psychosis. They explore the medical presentations compared with primary psychiatric manifestations and how to narrow the differential. Furthermore, Dr. Barlock discusses the management of psychotic patients from the ED perspective while Dr. White provides invaluable insight into their respective psychiatric care. Educational Pearls: Auditory hallucinations are more consistent with primary psychiatric psychosis, whereas visual hallucinations are indicative of drug-induced or withdrawal psychosis. Negative symptoms in schizophrenia can be remembered by the four A’s: Alogia, Affect, Ambivalence, and Associations. Typical primary psychosis presents before age 40, except for in perimenopausal and post-partum women, who are at higher risk of psychiatric psychosis. Medical etiology clues: acute and rapid onset, focal neurologic deficits, abnormal vital signs (especially fever), drugs, endocrine sources, autoimmune diseases, infectious disease, and brain lesions. To LP or not to LP? Dr. Barlock discusses indications for LP including fever, rapid onset, and change in level of consciousness.    Summarized by Jorge Chait, OMSI | Edited by Jorge Chalit, OMSI | Studio production by Jeffrey Olson