BACKGROUND: In the context of substantial financial disinvestment from alcohol and drug treatment services in England, our aim was to review the existing evidence of how such disinvestments have impacted service delivery, uptake, outcomes and broader health and social implications.

METHODS: We conducted a systematic review of quantitative and qualitative evidence (PROSPERO CRD42020187295), searching bibliographic databases and grey literature. Given that an initial scoping search highlighted a scarcity of evidence specific to substance use treatment, evidence of disinvestment from publicly funded sexual health and smoking cessation services was also included. Data on disinvestment, political contexts and impacts were extracted, analysed, and synthesized thematically.

RESULTS: We found 20 eligible papers varying in design and quality including 10 related to alcohol and drugs services, and 10 to broader public health services. The literature provides evidence of sustained disinvestment from alcohol and drug treatment in several countries and a concurrent decline in the quantity and quality of treatment provision, but there was a lack of methodologically rigorous studies investigating the impact of disinvestment.

CONCLUSIONS: This review identified a paucity of scientific evidence quantifying the impacts of disinvestment on alcohol and drug treatment service delivery and outcomes. As the global economy faces new challenges, a stronger evidence base would enable informed policy decisions that consider the likely public health impacts of continued disinvestment.