Abstract
Both Attention-Deficit/Hyperactivity Disorder (ADHD) and Obsessive-Compulsive Disorder (OCD) are associated with choice impulsivity, i.e. the tendency to prefer smaller immediate rewards over larger delayed rewards. However, the extent to which this impulsivity is mediated by shared or distinct underlying neural mechanisms is unclear. Twenty-six boys with ADHD, 20 boys with OCD and 20 matched controls (aged 12–18) completed an fMRI version of an individually adjusted temporal discounting (TD) task which requires choosing between a variable amount of money now or £100 in one week, one month or one year. Activations to immediate and delayed reward choices were compared between groups using a three-way ANCOVA. ADHD patients had steeper discounting rates on the task relative to controls and at a trend-level relative to OCD patients. OCD patients did not differ from controls. Patients with ADHD and OCD showed predominantly shared activation deficits during TD in fronto-striato-insular-cerebellar regions responsible for self-control and temporal foresight, suggesting that choice impulsivity is mediated by overlapping neural dysfunctions in both disorders. OCD patients alone showed dysfunction relative to controls in right orbitofrontal and rostrolateral prefrontal cortex, extending previous findings in these regions in OCD during cognitive control tasks to the domain of choice impulsiveness.
Original language | English |
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Pages (from-to) | 97-105 |
Journal | Psychiatry Research. Neuroimaging |
Volume | 269 |
Early online date | 12 Sept 2017 |
DOIs | |
Publication status | Published - 30 Nov 2017 |
Keywords
- ADHD
- OCD
- fMRI
- discounting
- reward
- impulsivity