Purpose: This study aims to examine the relationship between perceived social support, insight, and treatment adherence in patients with schizophrenia and bipolar disorder. 
 Materials and Methods:This study was conducted with 110 individuals, 55 of whom were bipolar and 55 patients with schizophrenia, who received inpatient treatment in the last 1 year, were in remission. Sociodemographic and clinical data form, Young Mania Rating Scale (YMDS), Clinical Global Impressions Scale (CGI), Schedule for Assessment of Insight (SAI), Morisky Medication Adherence Scale (MMAS), and Multidimensional Scale of Perceived Social Support (MSPSS) were administered to the participants. 
 Results: The mean age was 40.47±12.96 for bipolar patients and 40.45±11.71 for schizophrenics. Perceived family, friend, significant others support, and total support was found to be higher (p=0.000, p=0.000, p=0.004, p=0.000, respectively) in bipolar patients, and the highest support was perceived from family, followed by friends and significant people. Although the groups did not differ in terms of treatment adherence (p=0.083), the insight score was significantly higher in bipolar patients (p=0.001). Groups were evaluated with hierarchical regression analysis in terms of factors affecting perceived social support. Gender, years of education, insight, and treatment adherence were found to be predictive of social support (p=0.04, p=0.01, p