The impact of cash and near-cash social policies on substance use outcomes: a scoping review.

Background: The impact of government financial assistance and substance use is contested by 2 competing hypotheses: the "income effect" posits that cash transfers could facilitate substance consumption, while the "stress-relief hypothesis" posits that cash transfers alleviate poverty-related stress that contributes to substance use. Methods: We conducted a scoping review of 46 studies (2000-2025) evaluating US cash and near-cash safety net programs on substance use outcomes, following PRISMA-ScR guidance. Results: Evidence was most robust for tax credits, the Earned Income Tax Credit and Child Tax Credit, reducing tobacco use, particularly among lower-educated mothers. Evidence was suggestive but design-limited for Unemployment Insurance buffering overdose mortality in contexts of job loss, as most studies were ecological. Findings on alcohol and opioid outcomes were generally limited or null. Restrictions in near-cash supports, including drug-felony bans on the Supplemental Nutrition Assistance Program, were associated with higher rates of opioid misuse and substance use disorders. Disbursement design also mattered: lump-sum disability payments and synchronous COVID-era stimulus disbursements were linked to short-term spikes in overdose mortality ("check effect"), while stable, smaller benefits supported treatment retention. Conclusions: The US safety net plays a meaningful role in substance-related outcomes, with evidentiary strength varying considerably by program and substance.