Differential neural processing of value during decision-making in adults with attention-deficit/hyperactivity disorder and healthy controls

BACKGROUND: Risk-taking behaviours are observed among adults with attention-deficit/hyperactivity disorder (ADHD). We sought to evaluate altered neural processing of stimuli values associated with risk-taking decision behaviour, distinct from learning requirements, among adults with ADHD. METHODS: Overall, 32 adults with ADHD and 32 healthy controls without ADHD underwent a lottery choice task in a functional magnetic resonance imaging (fMRI) experiment. Participants accepted or rejected stakes with explicit information about variable probabilities of winning or losing points at different magnitudes. Outcomes were independent across trials, circumventing reward learning. Data analysis explored group differences in neurobehavioural responses to stimuli values during choice decision-making processing and outcome feedback. RESULTS: Compared with healthy controls, adults with ADHD had slower response times and tended to accept more stakes with a middle-to-low probability of winning. Adults with ADHD had evidence of lower dorsolateral prefrontal cortex (DLPFC) activity and reduced sensitivity in the ventromedial prefrontal cortex (VMPFC) region of interest in response to linear changes in probability, compared with healthy controls. Lower DLPFC responses were associated with lower VMPFC probability sensitivity and greater risk-taking among healthy controls but not adults with ADHD. Compared with health controls, adults with ADHD showed higher responses to loss outcomes in the putamen and hippocampus. LIMITATIONS: Assessments of real-life decision behaviours are required to further validate the experimental findings. CONCLUSIONS: Our findings explore tonic and phasic neural processing of value-related information that modulates risk-taking behaviours among adults with ADHD. Dysregulated neural computation of the values of behavioural actions and outcomes in the frontostriatal circuits may underlie decision processing distinct from reward learning differences among adults with ADHD. CLINICAL TRIAL REGISTRATION: NCT02642068