Stimulant Treatment Gap in ADHD Patients with Heroin Use Disorder: Clinical and Behavioural Consequences

Abstract

Highlights: Public health relevance—How does this work relate to a public health issue? Adults with ADHD and heroin use disorder are usually treated with opioid agonist therapy, while ADHD-specific pharmacotherapy is often withheld in addiction services. This treatment gap affects a high-risk population with complex psychiatric needs and significant public mental health impact. Public health significance—Why is this work of significance to public health? ADHD patients with heroin use disorder on opioid agonist therapy alone show greater emotional dysregulation, impulsivity, and cocaine use than those receiving ADHD pharmacotherapy. These findings indicate that current care models may insufficiently address core ADHD symptoms in dual-diagnosis patients. Public health implications—What are the key implications or messages for practitioners, policy makers and/or researchers in public health? Integrated treatment models combining addiction care with ADHD-specific interventions should be considered for dual-diagnosis populations. Further longitudinal research is needed to evaluate the safety and effectiveness of combining stimulant treatment with opioid agonist therapy. Background: Adults with attention-deficit/hyperactivity disorder (ADHD) often have comorbid substance use disorders (SUDs). In Italy, individuals with both ADHD and heroin use disorder (HUD) are usually treated in addiction services with opioid agonist therapy (OAT), but stimulant medications are rarely prescribed. This may create a treatment gap for core ADHD symptoms. Aim: This study examined the clinical and behavioural profiles of ADHD patients with HUD who receive OAT but no stimulant treatment, compared to ADHD patients without opioid use disorder (ADHD/NoHUD) on standard pharmacotherapy. All participants were considered treatment responders in their respective services. Methods: Data were collected from two outpatient clinics and included 103 adult ADHD patients assessed using validated tools for symptom severity, emotional dysregulation, and global functioning. Differences between groups were analysed using univariate tests and logistic regression. Results: The ADHD+HUD group was significantly older and showed higher levels of emotional dysregulation, impulsivity, and current cocaine use. Despite clinical stability, these individuals presented a more severe psychopathological profile than their ADHD/NoHUD counterparts, who received stimulant-based treatment. Conclusions: Although limited by its cross-sectional nature and setting-related confounders, the study indicates that OAT alone may not be sufficient to manage neurodevelopmental symptoms in ADHD+HUD patients. Further research is necessary to assess the safety and efficacy of integrated stimulant-based treatments, ideally within dual disorder services combining psychiatric and addiction expertise.