Othello syndrome refers to an irrational belief in a spouse's or partner's unfaithfulness. This condition predominantly affects men, though women can also experience it. It is marked by baseless accusations of cheating, relentless attempts to find proof, continuous questioning of the partner, fidelity tests, and sometimes even stalking. The syndrome can occur independently or alongside paranoid disorders, obsessive behaviors, or substance abuse. Much like the tragic events in Shakespeare's "Othello," this syndrome can lead to severe consequences, including marital breakdown, homicide, or suicide.The term "Othello syndrome" was coined by English psychiatrist John Todd (1914-1987), who, alongside K. Dewhurst, explored the condition in their 1955 paper titled "The Othello Syndrome: A Study in the Psychopathology of Sexual Jealousy" published in the Journal of Nervous and Mental Disease. Todd is also known for identifying the Alice in Wonderland syndrome. Other names for Othello syndrome include delusional jealousy, erotic jealousy syndrome, morbid jealousy, Othello psychosis, and sexual jealousy.