A systematic review and meta-analysis of global and social functioning among people at risk of bipolar disorder

BACKGROUND: Functional status could predict development of bipolar disorder (BD) or have clinical significance. The relationship between BD risk and functioning is poorly understood. We undertook a systematic review examining the global and social functioning of those at risk for BD. METHODS: We examined observational studies comparing a risk sample with healthy controls or full-threshold BD participants, using measures of global or social functioning. Risk status included family history of BD, meeting risk criteria, or having prodromal symptomatology, or premorbid functioning of persons with BD. Medline, PsycINFO, and Embase were searched. The Newcastle-Ottawa Scale for Cross-Sectional Studies was used to assess quality. Meta-analyses were performed where possible. RESULTS: 7215 studies were screened and 40 studies were included (8474 participants). Risk samples had poorer functioning than controls, and superior functioning to participants with BD. Meta-analysis indicated poorer global functioning among persons with familial risk compared to healthy controls (mean global functional difference: 5.92; 95 % confidence interval: 7.90, 3.95; mean premorbid functioning difference: 2.31; 95 % confidence interval: 0.70, 3.92). Studies with higher proportions of female participants had slightly poorer global functioning. High heterogeneity was attributable functional measures and potentially functionally differential subgroups within the risk samples. LIMITATIONS: Broader measures of functioning, such as neurocognition and behavioural measures, were excluded. Measures of global functioning are limited by conflating functioning and symptoms. CONCLUSIONS: Functioning in the BD risk populations is intermediate to that of healthy controls and persons with BD, indicating their value in definitions of BD risk, in itself a likely heterogeneous state.