Single-blind, randomized controlled trial of effectiveness of Naikan therapy as an adjunctive treatment for schizophrenia over a one-year follow-up period

Background: Current treatments for schizophrenia are often only partially effective.

Aims: Assess the possible benefit of using adjunctive Naikan therapy, a cognitive approach based on self-reflection that originated in Japan for the treatment of schizophrenia.

Methods: After resolution of acute psychotic symptoms, 235 psychiatric inpatients with schizophrenia who had a middle school education or higher were randomly assigned to a control group (n=112) that received routine medication and inpatient rehabilitative treatment or an intervention group (n=123) that also received adjunctive Naikan therapy for 2 hours daily, 5 days a week for 4 weeks. The patients were then discharged and followed up for 12 months. The Positive and Negative Syndrome Scale (PANSS), Personal and Social Performance scale (PSP), and Insight and Attitude Questionnaire (ITAQ) were used to assess patients at enrollment, after the 1-month intervention, and after the 12-month follow-up. Evaluators were blind to the group assignment of patients.

Results: Only 13 (10.6%) of the intervention group participants relapsed over the 12-month follow-up, but 23 (20.5%) control group participants relapsed (X(2)=4.50, p=0.034). Using a modified intention-to-treat analysis and a repeated measure analysis of variance, the PANSS, PSP, and ITAQ total scores all showed significantly greater improvement over the 12-month follow-up in the Naikan group than in the control group. The drop in mean chlorpromazine-equivalent dosage from enrollment to the end of follow-up was significantly different in the intervention group but not in the control group, though the change in dosage over time between groups was not statistically significant.

Conclusions: This study provides robust support for the effectiveness of Naikan therapy as an adjunctive treatment during the recovery period of schizophrenia. Compared to treatment as usually, adjunctive Naikan therapy can sustain the improvement in psychotic symptoms achieved during acute treatment, improve insight about the illness, enhance social functioning, and reduce relapse over a one-year follow-up period. Further research of this treatment with larger and more diverse samples of patients with schizophrenia is merited.