What are the mental illnesses that can cause psychosis?

Schizophrenia et al. Psychosis, or impaired contact with reality, as with hallucinations or delusions, is a possible symptom of many mental disorders and can also be caused by substances or prescription medications (side-effects). While psychosis is perhaps most associated with schizophrenia and other psychotic disorders, it can also occur in patients with depressive and bipolar disorders.