Psychosis-like syndrome associated with intermittent intracranial hypertension caused by a large arachnoid cyst of the left temporal lobe

Lesions on certain brain areas can cause psychiatric signs. Symptomatic arachnoid cysts can produce a variety of symptoms like headache, seizures, increased ICP, and rarely psychiatric disorders. We report a case of a young woman with a left temporal lobe arachnoid cyst, presented with headache and an atypical psychosis. A 72-h epidural ICP recording revealed incidental elevation of ICP. After a permanent shunt was placed, patient's symptoms improved substantially, and antipsychotic medication was significantly reduced.