A recent meta-analysis showed that long-acting injectable (LAI) antipsychotics were not superior to oral antipsychotics for preventing relapse in patients with schizophrenia. We therefore designed a treatment strategy combining risperidone LAI and COMPASS (COMprehensive Psycho-educational Approach and Scheme Set), an original psychoeducational program supporting treatment with risperidone LAI and evaluating subjective treatment satisfaction, transition of symptoms, and effectiveness in preventing symptomatic relapse. The aim of this study was to examine whether addition of COMPASS to risperidone LAI was more effective in preventing relapse in schizophrenia patients than risperidone LAI alone, with the latter group consisting of patients enrolled in a Phase III trial of risperidone LAI in Japan. Patients were followed up for 6 months, with COMPASS continuously implemented from the transition to the observation phase. The primary efficacy measurements were relapse rate (rates of rehospitalization and discontinuation due to inefficacy). Secondary efficacy measurements were the Brief Psychiatric Rating Scale (BPRS) and Global Assessment of Functioning (GAF) scores. Of the 96 patients originally enrolled, 19 (19.8%) were discontinued from all causes. During the 6-month study period, ten of the 96 patients (10.4%) relapsed, compared with a 12.2% relapse rate in patients enrolled in a Phase III trial of risperidone LAI in Japan. Patients showed significant improvements in BPRS total scores (P = 0.0031), BPRS positive (P = 0.0451), BRPS negative (P < 0.0001), and general subscale scores (P = 0.0031), and GAF (P < 0.0001) from baseline to 6 months. In conclusion, the lower relapse rate observed in patients treated with COMPASS plus risperidone LAI than in patients treated with risperidone LAI alone suggests that COMPASS may have benefits in the treatment of schizophrenia, indicating a need for randomized, controlled trials in larger numbers of patients.