Background: The association between emotional dysregulation (ED) and attention-deficit/hyperactivity disorder (ADHD) has been widely documented. However, a consensus has yet to be reached on how to conceptualize this domain within ADHD. Particularly, ADHD + ED may represent a distinct condition, a more severe ADHD, or a comorbidity. We explored these three main hypotheses, investigating clinical differences between patients with ADHD, ADHD + ED, and ED. Methods: In total, 101 participants (ages 18–50) were recruited and divided into four groups: ADHD (N = 23), ED (N = 28), ADHD + ED (N = 27), and HC (N = 23). ADHD and ED were assessed using the Diagnostic Interview for ADHD in adults (DIVA-5) and the Wender–Reimherr Adult Attention Deficit Disorder Scale (WRAADDS). Sociodemographic and clinical variables were compared among the groups. Results: Participants with ADHD and ADHD + ED exhibited comparably high ADHD severity and executive dysfunction ratings. While participants with ADHD + ED shared elevated negative emotionality and higher rates of mood disorders and anxiety disorders with participants with ED compared with those with ADHD, they showed specifically increased developmental and disruptive comorbidities, as well as earlier onset and greater cyclicity of comorbid mood disorders. Psychosocial functional impairments were similarly elevated on average in ADHD + ED and ADHD, but ADHD + ED showed more pronounced and widespread deficits across multiple domains. Conclusions: ADHD + ED is unlikely to represent a more severe form of ADHD but may be more appropriately conceptualized as either a distinct entity or a “comorbid” phenotype. Comparisons with ED without ADHD highlighted clinical features specific to ADHD + ED, including a higher neurodevelopmental load, impulse-control disorders, and a poorer course of mood disorders.

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.

Background: Emotional dysregulation and impulsivity represent key risk factors for adverse trajectories in adults with ADHD and are frequently observed among patients with opioid use disorder (OUD). Levomethadone, the R-enantiomer of methadone, provides more stable dopaminergic modulation than the racemic formulation and may improve emotional control. The primary objective was to examine emotional, clinical, and substance use changes after the switch to levomethadone and to determine whether these trajectories differed according to ADHD screening status. This study evaluated emotional, clinical, and behavioral outcomes—including substance use—after transitioning from racemic methadone to levomethadone maintenance therapy, focusing on the moderating role of ADHD symptoms and dose escalation. Methods: Eighty-three OUD patients in methadone maintenance were assessed at baseline, T1 (mean = 2.13 months, SD = 0.65), and T2 (mean = 6.20 months, SD = 0.91). Emotional dysregulation (RIPOST), clinical severity (Clinical Global Impression), and days of substance use were analyzed using Linear Mixed Models (participants with ≥1 valid follow-up). ADHD symptoms (Adult ADHD Self-Report Scale DSM-5) were evaluated with Wilcoxon signed-rank tests. Dose escalation (↑levomethadone) was defined as ≥1 increase during follow-up and was only included in the mixed models. Substance use analyses were restricted to baseline active users. Results: Emotional impulsivity significantly decreased over time only in participants screening positive for ADHD symptoms (ASRS ≥ 14), independent of dose escalation. Emotional instability also declined but across the full cohort. CGI scores improved in all participants. Substance use patterns showed a modest overall improvement, with reductions most evident for sedatives and alcohol. The findings indicate a specific effect of levomethadone on affective regulation and clinical stabilization, particularly in individuals with impulsivity traits. Conclusions: Levomethadone maintenance appears to improve emotional regulation and global functioning beyond dose-related effects, supporting its potential value in complex OUD patients with clinically relevant ADHD symptomatology. Combined treatment with levomethadone and methylphenidate may further enhance executive control and craving regulation in this population.