INTRODUCTION|Community Mental Health Centers (CMHC) were established to provide psychosocial support services for patients with severe mental disorders such as bipolar disorder, schizophrenia, unspecified schizophrenia spectrum and other psychotic disorder. The aim of our study was to determine the effects of participation frequency in a CMHC on insight, treatment adherence and functionality in severe mental disorders.¤METHODS|362 patients diagnosed with bipolar disorder and psychosis according to the DSM–5 criteria and treated in CMHC were included in this retrospective study. The participation frequency of patients benefited from CMHC services for a year was retrospectively screened. The patients had been evaluated with Clinical Global Impression Scale (CGI), Medication Adherence Rating Scale (MARS), Global Assessment of Functioning (GAF), and Schedule for Assessing the Three Components of Insight (SATCI), and Functional Remission of General Schizophrenia Scale (FROGS). Patients were divided into two groups as bipolar disorder and psychosis (schizophrenia, schizoaffective and USS&OPD).¤RESULTS|The patients had been participated in CMHC services in 6 different frequency groups: 68 (18.8%) once in six months, 62 (17.1%) once in three months, 68 (18.8%) once in two months, 98 (27.1%) once/twice a month, 34 (9.4%) once/twice a week, 32 (8.8%) three/four times a week, respectively. There were significant differences between GAF, CGI, SATCI, MARS, FROGS scores in terms of participation frequencies of psychosis group and there were significant differences between GAF, CGI, MARS scores in terms of participation frequencies of bipolar disorder group at the end of one year. ¤DISCUSSION AND CONCLUSION|In general, as the participation frequency increased, insight, treatment adherence and functionality increased. In addition to individual factors, our results will also contribute to determine the frequency of participation in CMHC.¤