"In a 2017 article in the journal Psychological Medicine, researcher Marta Rapado-Castro and colleagues reported that among 58 patients with bipolar disorder or schizophrenia and symptoms of psychosis, those who took two grams per day of the antioxidant n-acetylcysteine (NAC) showed improvements in working memory after six months compared to those who took placebo over the same study period.Antipsychotic medications can typically reduce psychotic symptoms such as delusions or hallucinations, but cognitive symptoms such as problems with learning, memory, or information processing may remain. NAC, which is sold over-the-counter as a nutritional supplement, seemed to improve these symptoms.The researchers suggest that larger studies of NAC are needed, particularly to determine whether giving NAC to patients during their first episode of psychosis could prevent cognitive decline from occurring at all during the course of their illness.NAC has been found to have a range of benefits, including reducing substance abuse and interfering with habit-based behaviors such as compulsive hair-pulling, obsessive-compulsive disorder, and gambling.Researcher Michael Berk, a co-author of the study, reported in the journal Biological Psychiatry in 2008 that NAC could also improve depressive symptoms in bipolar disorder and negative symptoms in schizophrenia."
It's also beneficial in the overall treatment of schizophrenia, bipolar disorder, bipolar depression, and other conditions.