OBJECT: This study was carried out to evaluate immunologic difference between baseline and after 4 weeks drug treatment with atypical antipsychotics (rispreidone) by measurement of serum concentration of 6 cytokines. METHODS: The subjets were composed of 25 patients who are admitted at Dajeon St's Marys hospital of psychiatry department and diagnosed as schizophrenia by DSM-IV diagnositc criteria. We measured serum IL-1beta, IL-2, IL-6, IL-12, INF-gamma, TNF-alpha concenatrations by quantitative ELISA method using ELISA kit (Endogen Inc., Woburn, MA, USA).The two psyciatrists performed PANSS examination between baseline and after 4 weeks risperidone treatments. RESULTS: The serum level of IL-12 was increased significantly after medication of 4 weeks and the serum concentration of IFN-gamma showed the tendency of decreasement but not significant. The serum level of the other cytokines showed no significant change. CONCLUSIONS: We spectulate that the increasement of IL-12 may contribute to role of activation of immune response by treatment of antipsychotic medication (risperidone). This study is first trial of IL-12 study in neuropsychiatric field and IL-12 which play important role of immune response becomes interesting subjects in immune research.