[The psychosis epidemiology in Turkey: a systematic review on prevalence estimates and admission rates]

To provide prevalence estimate, admission rates and related features of psychotic disorders in Turkey.

Studies with data on prevalence and/or rates in outpatient or inpatient admissions after 1990 were included. Strings of ([schizo*OR psych*] AND Turkey) were used in PubMed and PsychINFO to detect relevant studies. Turkish Medical and Psychiatry indexes were screened with Turkish keywords. Abstract books of national congresses, national index of thesis, and references of the included papers were searched for additional data. Results were presented as prevalence per 1000 and median values of admission rates.

A total of 56 studies were included, including 8 cross-sectional (4 core and 4 special group), 27 outpatient and 21 inpatient admission estimates or rates. The lifetime prevalence of schizophrenia in general population (pooled data, n: 6022) was 8.9 per 1000 (Standard error [SE]: 1.2; 95% confidence interval [CI]: 6.6-11.3). Psychosis prevalence is higher in subgroups including university students, prisoners and homeless people. Patients with a diagnosis of psychotic disorder constituted 7.6% and 26.9% of adult outpatient and inpatient psychiatry admissions. However, median rates vary depending on institutional, regional, temporal and residential features. Male gender was at higher risk in all kinds of estimates and rates for all age groups.

Prevalence of schizophrenia in Turkey is higher than the formerly reported estimates in different countries. Higher prevalence may be a consequence of sample properties, environmental risk exposures, and study design. However more research is needed to further elaborate the relatively higher prevalence. Nevertheless, a major part of the psychiatry services are devoted to psychotic outpatients and inpatients.