OBJECTIVES: To systematically review evidence of the clinical effectiveness of psychosocial interventions for adults with substance use disorder that have a co-occurring common mental health disorder or borderline personality disorder. To identify papers that estimate the cost-effectiveness of interventions for patients with substance use disorder and common mental health disorder or borderline personality disorder.

METHODS: An umbrella review (a systematic review of systematic reviews) for clinical effectiveness was conducted. Systematic database searches [MEDLINE, EMBASE, PsycInfo (American Psychological Association, Washington, DC, USA), Cochrane Database of Systematic Reviews, and Web of Science] were carried out in February 2024. Inclusion criteria: Adults with substance use disorder and common mental health disorder or borderline personality disorder; psychosocial interventions (with or without pharmacological therapies); comparators psychosocial treatments, treatment as usual, waitlist/no treatment; systematic reviews of randomised controlled trials. Data, including critical appraisal, were extracted into a standardised form by one reviewer, and checked by another. Data were discussed in a narrative review. A literature review of MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, and EconLit were undertaken to identify cost-effectiveness papers. An illustrative model was constructed to show how cost-effectiveness could be calculated if data were available.

RESULTS: Of 5420 unique records, 30 systematic reviews were included in the clinical review. The methodological quality of the reviews was generally good. Most of the interventions and many of the active comparators studied resulted in some improvement for patients. Most reviews focused on depression, anxiety or post-traumatic stress disorder; there were some looking at mixed common mental health disorder or borderline personality disorder. There was much heterogeneity both between reviews, and between the randomised controlled trials within the reviews. The results suggested integrated treatment for co-occurring diagnosis patients may be better for common mental health disorder outcomes than treatment as usual of parallel uncoordinated services. One study was identified that met the cost-effectiveness criteria. However, this reported results alongside a clinical study and was not a modelling paper. The illustrative model should aid future researchers.

LIMITATIONS: Heterogeneity made it difficult to reach an overall conclusion about which therapies were best. Most reviews stated the results were not generalisable across all populations or settings. There were few reviews of borderline personality disorder; or of common mental health disorder other than anxiety/depression/post-traumatic stress disorder.

FUTURE WORKS: Future research comparing integrated with parallel or sequential treatment, with follow-up of 6 months or longer, and sample size large enough to encompass dropout, may be beneficial.

CONCLUSIONS: No implications for current practice could be recommended due to heterogeneity of reviews/randomised controlled trials within reviews.