Unique and Transdiagnostic Dimensions of Reward Functioning in Attention-Deficit/Hyperactivity Disorder and Alcohol Use Disorder Symptoms

AIMS: Contemporary theories of attention-deficit/hyperactivity disorder (ADHD) and alcohol use disorder (AUD) emphasize core dysfunctions in reward-related processes and behaviors as pathognomonic characteristics. However, to date, it is unclear which domains of reward functioning are unique to ADHD versus AUD symptom dimensions, and which represent underlying shared correlates. METHODS: The current study employed secondary data analyses from a large community sample of emerging adults (N = 602; 57.3% female) and novel transdiagnostic modeling (i.e. bi-factor confirmatory factor analyses and structural equation modeling) of ADHD, AUD and shared symptom dimensions to identify unique and common reward-related dimensions: environmental suppressors, reward probability, hedonic capacity, proportionate substance-related reinforcement and delay discounting. RESULTS: The presence of environmental suppressors was the only reward-related construct that correlated with the underlying ADHD-AUD shared dimension. The AUD symptom dimension was uniquely associated with proportionate substance-related reinforcement, whereas the ADHD symptom dimension was uniquely associated with limited reward probability. No significant associations were found for delay discounting or hedonic capacity. CONCLUSIONS: These novel findings highlight specific aspects of reward-related functioning in ADHD, AUD and shared symptom dimensions. In so doing, this work meaningfully advances theoretical conceptualizations of these two commonly co-occurring presentations and suggests future directions for research on transdiagnostic correlates. Future longitudinal studies should include clinical samples with diagnoses of AUD and ADHD to further identify underlying correlates over time.