The research was conducted to determine the effect of TSH level on the disease of individuals diagnosed with schizophrenia. In this retrospective study, the files of 2552 patients who received inpatient treatment at the Psychiatric Clinic of Gazi University Faculty of Medicine between Dec 2010 and 2020 were retrospectively scanned. October 2010-2020 “Personal Information Form” was used to collect research data and this form consists of thirteen questions, including TSH level in addition to data such as age, gender obtained from archival records between Dec 2010-2020. The mean age of the sample was 38.92±10.80 and it was found that 74% (n=77) were male, 40.4% (n=42) were high school graduates, 67.3% (n=70) were single and 54.8% (n=57) were not working. Blood TSH values compared according to sociodemographic variables gender (U=963,5, Z=-0,564, p=0,573), education (X2=0,353, p=0,838), marital status (U=974,5, Z=-1,494, p=0,135), and occupation (X2=3,334, p=0,504), it was found that showed significant differences according to. While the blood TSH values did not show a significant difference according to the drug treatment used (U=52.0, Z=-1.351, p=0.177), they showed a significant difference according to the presence of psychiatric illness in the family (U=858.0, Z=-2.502, p=0.012). As a result, it has been found that TSH value is an important hormone in individuals with schizophrenia. In particular, more research and data are needed in order to assess whether TSH value shows low or high value according to mental illnesses.