Factors affecting social functioning of schizophrenia patients include neuro-cognitive functioning, social cognition, performance competences (interpersonal skills and task-related competence), intrinsic motivation, meta-cognition, self-awareness, support environments provided by others such as family members, and psychiatric symptoms. Studies mainly involving meta-analyses of psychosocial interventions targeting each factor were reviewed, and appropriate interventions to improve social functioning were discussed.
 The effect size of cognitive rehabilitation was small-medium for both neuro-cognitive functioning and social functioning. Concerning social cognition interventions, their significant effects have been reported in domains such as the perception of facial expression, which have established assessment methods, while their effects on social functioning have been inadequate. After interpersonal skill interventions such as social skills training, improvement in the target skills and negative symptoms was observed, but the effect size for social functioning was small-medium. On task-related competence, provision of work places and interventions (supported employment) to enhance competences there had definite effects. The effects of interventions targeting specified meta-cognition were reported, but their effects on social functioning were not adequately confirmed. Interventions to improve self-awareness/disease-awareness remain pioneering. In recent years, interventions to improve decreased volition/motivation and negative symptoms have been reported. Interventions for positive symptoms were reported to have modest effects. Families, care providers, and environmental support had effects on the quality of life and prevention of relapse. Programs targeting multiple factors related to social functioning are expected to be able to improve social functioning. Based on the above results, the following 3 points are proposed:
 ・Models that provide direct support in real life and aim at improvement in necessary functions, not stepwise functional improvement, may be useful.
 ・Since the effect sizes of interventions targeting a single factor such as neuro-cognitive functioning are not large, comprehensive interventions aiming at improvement in social functioning in real life should be planned.
 ・Development and dissemination of environmental support are necessary.
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