Family, twin and adoption studies of severe mental disorders in sub-Saharan Africa: a scoping review.

Purpose: The traditional genetic epidemiological studies are necessary to improve accurate risk communication to service users and their families. This scoping review aimed to describe the volume and scope of existing research evidence on family, twin and adoption studies of severe mental disorders (SMDs) in SSA. This is with a view to identifying gaps in the literature and the adequacy of data for a systematic review and meta-analysis.

Methods: Literature search was done for all original peer-reviewed research articles on the topic in SSA using PubMed and MEDLINE. Publications included were peer-reviewed original articles, irrespective of their quality, carried out in the region from the 1970s till 9th March, 2022, which were available in English or translated to English. Case reports, abstracts, and studies among populations living outside the region were excluded.

Results: A total of five studies that met the inclusion criteria across the 46 countries in the region were identified. Of the three thematic areas of focus, only family studies on SMDs had research work in SSA. These studies provided evidence of familial clustering of SMDs in SSA. There were no twin and adoption studies on SMDs in the region. However, the review noted the establishment of two twin registries in Guinea-Bissau and Nigeria. A huge gap exists in the area of twin and adoption studies on SMDs in SSA.

Conclusion: The volume of research evidence on traditional family genetic studies of SMDs is grossly inadequate to consider a systematic review in SSA. We have suggested studies to remedy the situation.