Impact of ADHD on the neurocognitive functioning of adolescents with bipolar disorder
Background: Pediatric Bipolar Disorder (BD) has been associated with a number of neurocognitive deficits not dissimilar to ADHD. This study compared neuropsychological profiles of 4 groups of adolescents (14–17 years): 41 Normal Controls (NC), 30 ADHD, 12 BD and 12 combined (BD+ADHD). Methods: Participants were identified according to a standardized protocol (WASHU-KSADS mood section, K-SADS-PL and Conners Scales) and completed tests of processing speed, memory, executive functioning, set shifting, and inhibition. ADHD adolescents on stimulant medication did not take it on the day. Results: After controlling for covariates, the ADHD-only and combined groups were most impaired, including processing and naming speed, working memory, and response inhibition. The ADHD-only group showed specific impairment in naming objects, numbers and letters than the NC and showed greater deficits than the BD-only group on tests of naming speed. The combined group showed greatest deficits in verbal memory and inhibitory control. Other than working memory, there were no differences between the BD-only and NC groups. Removal of BD-NOS did not impact on the results. Conclusions: This study failed to find broad neurocognitive deficits in BD-only adolescents. Only those with comorbid ADHD showed cognitive deficits, highlighting the impact ADHD may have on neurocognitive functioning of BD.