Abstract: We found 14 studies that included siblings amongst other family members in receipt of psychoeducational interventions. However, we were only able to include one small trial with relevant and available data (n = 9 siblings out of n = 84 family member/carer-participants) comparing psychoeducational intervention with standard care in a community care setting, over a duration of 21 months. There was insufficient evidence to determine the effects of psychoeducational interventions compared with standard care on 'siblings' quality of life' (n = 9, MD score 3.80 95% CI -0.26 to 7.86, low quality of evidence), coping with (family) burden (n = 9, MD -8.80 95% CI -15.22 to -2.34, low quality of evidence). No sibling left the study early by one year (n = 9, RD 0.00 CI -0.34 to 0.34, low quality of evidence). Low quality and insufficient evidence meant we were unable to determine the effects of psychoeducational interventions compared with standard care on service users' global mental state (n = 9, MD -0.60 CI -3.54 to 2.38, low quality of evidence), their frequency of re-hospitalisation (n = 9, MD -0.70 CI -2.46 to 1.06, low quality of evidence) or duration of inpatient stay (n = 9, MD -2.60 CI -6.34 to 1.14, low quality of evidence), whether their siblings received psychoeducation or not. No study data were available to address the other primary outcomes: 'siblings' psychosocial wellbeing', 'siblings' distress' and adverse effects. Most studies evaluating psychoeducational interventions recruited siblings along with other family members. However, the proportion of siblings in these studies was low and outcomes for siblings were not reported independently from those of other types of family members. Indeed, only data from one study with nine siblings were available for the review. The limited study data we obtained provides no clear good quality evidence to indicate psychoeducation is beneficial for siblings' wellbeing or for clinical outcomes of people affected by SMI. More randomised studies are justified and needed to understand the role of psychoeducation in addressing siblings' needs for information and support.

Plain-language summary: . A search for randomised trials investigating psychoeducation for the siblings of people with severe mental illness was run in 2013. Results of the search suggest that brothers and sisters form a small proportion of family members participating in studies of this kind. Only one study meeting the review criteria was found. This study included nine siblings and compared a psychoeducational intervention with standard care in a community care setting, over a period of 21 months. . Better outcomes in terms of coping were identified for those siblings who received psychoeducation. However, the number of participants was small and the quality of evidence low, and there is no conclusive evidence that psychoeducation is of benefit for brothers/sisters in this and other important areas (such as wellbeing, quality of life) or for the outcomes of people with mental illness (such as mental state, hospital admission or length of hospital stay). . Further studies are needed to understand the role of psychoeducation in specifically helping brothers and/or sisters to cope with providing care for their mentally ill siblings. The scarcity of good quality studies means that it is not possible to assess which type of psychoeducation is the most effective, although interventions using a group format that brings many family members together to receive education and share their experiences seem well-received by the participants. This plain language summary has been written by a consumer: Ben Gray, Senior Peer Researcher, McPin Foundation.http://mcpin.org/