Attention-Deficit/Hyperactivity Disorder (ADHD) is overrepresented in patients with addictive disorders but remains underdiagnosed. This comorbidity complicates clinical presentations and worsens prognosis. We aimed to evaluate addictive disorder outcomes six months after ADHD diagnosis in patients undergoing addiction treatment and to identify factors associated with a favorable outcome. Secondary objectives explored patient characteristics and therapeutic strategies.

The START study (Study on the Treatment of ADHD and addiction comorbidity: a ReTrospective analysis of medical records) was an observational, retrospective analysis of electronic medical records from patients recently diagnosed with ADHD using the DIVA. Included patients had either substance use disorders (SUD) or behavioral addictions (eating, sex, gambling, gaming/screen use, shopping, and physical exercise), with diagnoses established by the referring physician according to clinical judgment, and attended at least two consultations six months apart. Descriptive analyses were conducted for the total sample and by clinical outcome, followed by multivariate logistic regression to identify predictors of improvement.

Tobacco and cannabis use disorders were the most common (61.3 % each). Psychiatric comorbidities were frequent (lifetime 84.6 %, current 34.1 %). Methylphenidate initiation was delayed in 29 % of cases, primarily due to current psychiatric comorbidities or ongoing addiction. Improvement in addictive disorders was observed in 61.3 % of patients. Favorable outcomes were associated with older age (OR = 1.13, 95 % CI [1.04–1.23], p = 0.006) and living as a couple (OR = 3.84, 95 % CI [1.10–13.42], p = 0.035), whereas poorer outcomes were associated with the ADHD combined presentation (reference group), compared with the predominantly inattentive and hyperactive/impulsive presentations (OR = 0.16, 95 % CI [0.03–0.90], p = 0.037).

The study highlights socio-demographic and clinical predictors of outcome, advancing our understanding of ADHD-addiction comorbidity. Findings warrant confirmation in prospective longitudinal research.