Cost-effectiveness evaluations of psychological therapies for schizophrenia and bipolar disorder: a systematic review

Objectives: This review aims to assess the cost-effectiveness of psychological interventions for schizophrenia/bipolar disorder (BD), to determine the robustness of current evidence and identify gaps in the available evidence.

Methods: Electronic searches (PsycINFO, MEDLINE, Embase) identified economic evaluations relating incremental cost to outcomes in the form of an Incremental Cost-Effectiveness Ratio (ICER) published in English since 2000. Searches were concluded in November 2018. Inclusion criteria were: adults with schizophrenia/BD; any psychological/psychosocial intervention (e.g. psychological therapy and integrated/collaborative care); probability of cost-effectiveness at explicitly-defined thresholds reported. Comparators could be routine practice, no intervention, or alternative psychological therapies. Screening, data extraction, and critical appraisal were performed using pre-specified criteria and forms. Results were summarised qualitatively. The protocol was registered on the PROSPERO database (CRD42017056579).

Results: Of 3,864 studies identified, 12 met the criteria for data extraction. All were integrated clinical and economic randomised controlled trials. The most common intervention was cognitive behavioural therapy (CBT, 6/12 studies). The most common measure of health benefit was the quality-adjusted life-year (QALY) (6/12). Followup ranged from 6-months to 5-years. Interventions were found to be cost-effective in most studies (9/12): the probability of cost-effectiveness ranged from 35-99.5%. All studies had limitations and demonstrated uncertainty (particularly related to incremental costs).

Conclusions: Most studies concluded psychological interventions for schizophrenia/BD are cost-effective, including CBT, though there was notable uncertainty. Heterogeneity across studies makes it difficult to reach strong conclusions. There is a particular need for more evidence in the population with BD and for longer-term evidence across both populations.