Self-medication of attention-deficit/hyperactivity disorder symptoms with psychoactive substances in adults: a scoping review of how symptom-relief motives are framed and operationalised across substances.

Introduction: Adults with attention-deficit/hyperactivity disorder (ADHD) use tobacco, cannabis, alcohol, cocaine and non-prescribed stimulants far more than the general population. The self-medication hypothesis holds that people with ADHD, including those undiagnosed, use substances to relieve core symptoms rather than for recreation or shared vulnerability to addiction, and is widely invoked to reframe illicit substance use as undiagnosed ADHD. How this claim is framed and tested has not been mapped across substances. Objective: To map the literature invoking self-medication of ADHD symptoms in adults, substance by substance, and to characterise how each source frames the concept relative to misuse, recreational or shared-liability accounts. Eligibility criteria: Empirical studies, reviews, commentaries, preprints and trial-register records on self-medication of ADHD symptoms with a psychoactive substance in adults or predominantly adult samples; English; inception to 21 July 2026. Information sources: PubMed, OpenAlex and Consensus, with ClinicalTrials.gov and a preprint search. Searches were conditioned on self-medication and motive terminology, so the corpus maps the self-medication literature and does not sample the misuse or shared-liability literature independently. Charting methods: Sources were charted for substance, design, population, operationalisation of self-medication, and a framing category (self-medication-framed; mixed; misuse- or shared-liability-framed; neutral/descriptive). A descriptive map was built by substance. No critical appraisal or evidence-strength ranking was made. Results: Of 937 records identified and 820 screened, 109 sources (1986-2026) met the criteria. Coverage was heaviest for non-prescribed stimulants (n=35), cannabis (n=29), nicotine (n=25) and alcohol (n=17); no eligible ketamine source was identified. Self-medication framing was most prevalent, and uniquely accompanied by experimental data, for nicotine; prevalent but observational for cannabis; coexisted with academic and recreational motives for stimulants; and alcohol was mostly framed as comorbidity or shared liability. Self-medication was overwhelmingly inferred from association or motive report rather than tested against symptom change. Conclusions: Self-medication framing is substance-specific in prevalence and accompanying evidence. Because the search was conditioned on self-medication terminology, the map describes how the literature frames the claim and does not adjudicate between competing accounts. Applying self-medication as a blanket explanation for substance use in people with ADHD symptoms is not warranted by how the claim has been tested.