Insomnia is a common comorbid condition in patients with schizophrenia. Accumulating evidence has suggested that sleep disturbance can be a risk factor for, or a prodromal symptom of psychosis; it can also aggravate psychotic symptoms, therefore interfering with the treatment of schizophrenia. Symptoms related to disordered sleep, including reduced sleep time and quality of sleep, often go untreated and persist as chronic, clinically significant insomnia. Notably, observed abnormalities in these polysomnographic traits have been shown to be heritable, thus further strengthening the argument for an etiological link between insomnia and schizophrenia. Clinical interest in this relationship has grown with the understanding that the presence of sleep disturbance, especially clinically significant insomnia, corresponds with reduced quality of life (QOL) and likely worse clinical outcomes for patients with schizophrenia. Recent studies have found that the increased risk for suicidal behavior in schizophrenia is associated with the unemployment, a family history of psychiatric disorder, lack of social support, higher level of insight, higher education level and hopelessness. Studies have investigated associations between insomnia and suicidal thinking and behavior in patients with schizophrenia. A retrospective study of 106 subjects with prodromal psychosis found that insomnia was associated with increased suicidal ideation, but not suicide attempt.