Common side effects include sleepiness, movement disorders, nausea, and diarrhea.[1] Serious side effects may include the potentially permanent movement disorder tardive dyskinesia, as well as neuroleptic malignant syndrome, an increased risk of suicide, angioedema, and high blood sugar levels.[1] In older people with psychosis as a result of dementia, it may increase the risk of dying.[1] Use during pregnancy is of unclear safety.[2] How it works is not clear but is believed to involve effects on dopamine and serotonin in the brain.[1]