There are minor subgroups where the risk is high. This risk is usually associated with a comorbid disorder such as a substance use disorder – in particular alcohol, or with antisocial personality disorder. Substance use disorder is strongly linked, and other risk factors are linked to deficits in cognition and social cognition including facial perception and insight that are in part included in theory of mind impairments. Poor cognitive functioning, decision-making, and facial perception may contribute to making a wrong judgement of a situation that could result in an inappropriate response such as violence. These associated risk factors are also present in antisocial personality disorder which when present as a comorbid disorder greatly increases the risk of violence. Epidemiology
In 2017, the Global Burden of Disease Study estimated there were 1.1 million new cases; in 2022 the World Health Organization (WHO) reported a total of 24 million cases globally. Schizophrenia affects around 0.3–0.7% of people at some point in their life. In areas of conflict this figure can rise to between 4.0 and 6.5%. It occurs 1.4 times more frequently in males than females and typically appears earlier in men.Worldwide, schizophrenia is the most common psychotic disorder.
An underlying factor of sudden cardiac death may be Brugada syndrome (BrS) – BrS mutations that overlap with those linked with schizophrenia are the calcium channel mutations. BrS may also be drug-induced from certain antipsychotics and antidepressants. Primary polydipsia, or excessive fluid intake, is relatively common in people with chronic schizophrenia. This may lead to hyponatremia which can be life-threatening. Antipsychotics can lead to a dry mouth, but there are several other factors that may contribute to the disorder; it may reduce life expectancy by 13 per cent. Barriers to improving the mortality rate in schizophrenia are poverty, overlooking the symptoms of other illnesses, stress, stigma, and medication side effects.Schizophrenia is a major cause of disability. In 2016, it was classed as the 12th most disabling condition. Approximately 75% of people with schizophrenia have ongoing disability with relapses. Some people do recover completely and others function well in society. Most people with schizophrenia live independently with community support. About 85% are unemployed. In people with a first episode of psychosis in schizophrenia a good long-term outcome occurs in 31%, an intermediate outcome in 42% and a poor outcome in 31%. Males are affected more often than females, and have a worse outcome. Studies showing that outcomes for schizophrenia appear better in the developing than the developed world have been questioned.