Psychosocial interventions for carers of people with severe mental and substance use disorders: a systematic review and meta-analysis.

Background: Severe mental disorders - such as schizophrenia, bipolar disorder, and substance use disorders - exert a negative impact not only on affected people but also on their carers. To support carers of people with severe mental disorders, several psychosocial interventions have been developed.

Methods: This systematic review and meta-analysis aimed to assess whether psychosocial interventions for carers of persons with schizophrenia, bipolar disorder, or substance use disorders produce benefit/harm with respect to a series of outcomes - including subjective and objective burden, depressive symptoms, well-being/quality of life, sleep, skills/knowledge, self-efficacy, physical health - as compared to standard support/support as usual or other control conditions.

Results: In carers of persons with schizophrenia, psychoeducational interventions were associated with significant improvement in personal burden, well-being, and knowledge about the illness; and a supportive-educational intervention with an improvement in personal burden. In carers of persons with bipolar disorder, psychoeducational interventions were associated with significant improvement in personal burden and depressive symptoms; family-led supportive interventions with an improvement in family burden; family-focused intervention and online "mi.spot" intervention with a significant reduction in depressive symptoms. Psychosocial interventions used for carers of persons with substance use disorders were found to be overall effective on the level of well-being, but the low number of trials did not allow detection of differences between the various psychosocial interventions.

Conclusions: The quality of the evidence ranged from very low to moderate, suggesting the need for further better-quality research.