Are psychosocial methods of intervention effective in schizophrenic patients? A meta-analysis

The global aim of this study is to define the influence of psychosocial methods of intervention on the feeling and behavior of schizophrenic patients as compared to patients in control groups (who received only the usual hospital treatment without specific methods of intervention). The method used to quantitatively examine this question was to carry out a meta-analysis of 31 studies, comprising an entire sample of 2,161 patients. For specific methods of intervention, the value of the weighted mean effect size (weighted with regard to sample size) was (r) over bar(g)=+0,17 (d=+0.34). To interpret this result, Rosenthal's (1984) binomial effect size display can be used: 59% of the patients who received specific methods of intervention improved, compared to only 41% of the control patients. The highest values are equal for familiy education and cognitive therapy, with a weighted mean effect size of (r) over bar(g)=+0.28 (d=+0.58). These results gain importance when one considers that psychosocial methods of intervention showed a larger effect compared to the non-specific control group treatment.