Economic evaluations of non-pharmacological interventions and cost-of-illness studies in bipolar disorder: A systematic review

•In all included economic evaluations the interventions resulted in improved clinical outcomes and in five cases also in less total costs.•The identified cost-of-illness studies showed a wide range of direct costs per patient per year ($881-$27,617) and indirect costs ($1568-$116,062).•Comparability of the studies was limited by heterogeneity and especially the field of economic evaluations of non-pharmacological interventions in bipolar disorder lacks evidence.•Even though limited, current evidence suggests that non-pharmacological interventions improve outcomes and may lead to cost-savings compared with TAU.•We suggest that future research should further investigate the cost-effectiveness of non-pharmacological interventions for bipolar disorder, use quality of life measures to evaluate effects and take study quality criteria into account when designing and conducting studies. Background Bipolar disorder (BD) is associated with substantial societal burden. Therefore, economic studies in BD are becoming increasingly important. The goal of the current study is three-fold: (1) summarize the evidence regarding economic evaluations (EEs) of non-pharmacological interventions for BD, (2) summarize cost-of-illness studies (COIs) for BD published 2012 or later and (3) assess the quality of the identified studies. Methods A systematic search was conducted in MedLine, EMBASE and PsycINFO. For both EEs and COIs, quality assessments were conducted and general and methodological characteristics of the studies were extracted. Outcomes included incremental-cost-effectiveness ratios for EEs and direct and indirect costs for COIs. Results Eight EEs and ten COIs were identified. The included studies revealed high heterogeneity in general and methodological characteristics and study quality. All interventions resulted in improved clinical outcomes. Five studies additionally concluded decreased total costs. For COIs, we found a wide range of direct ($881-$27,617) and indirect cost estimates per capita per year ($1,568-$116,062). Limitations High heterogeneity in terms of interventions, study design and outcomes made it difficult to compare results across studies. Conclusions Interventions improved clinical outcomes in all studies and led to cost-savings in five studies. Findings suggest that non-pharmacological intervention for BD might be cost-effective. Studies on the costs of BD revealed that BD has a substantial economic burden. However, we also found that the number of