Additive neurocognitive deficits in adults with attention-deficit/hyperactivity disorder and depressive symptoms.

The purpose of this study was to examine the possible additive neurocognitive deficits in adults with both attention-deficit/hyperactivity disorder (ADHD) and serious depressive symptoms. Participants were 54 university students who completed a psycho-educational assessment. Three groups were examined: a group with comorbid ADHD and elevated depressive symptoms (ADHD + DEP; N = 18); a group with ADHD only (N = 18); and a group with elevated depressive symptoms only (DEP; N = 18). Group differences were examined on a battery of neurocognitive tests. The ADHD + DEP group performed significantly worse than the other groups on processing speed tasks and delayed recall of conceptual verbal information and significantly worse than the ADHD group on shifting tasks. Depressive symptom severity was significantly correlated with processing speed, verbal memory performance, and shifting in the ADHD and ADHD + DEP groups. Results suggest that the co-occurrence of ADHD and depressive symptoms in adults is associated with additional neurocognitive impairment.

Examining unusual digit span performance in a population of postsecondary students assessed for academic difficulties.

Methods of identifying poor test-related motivation using the Wechsler Adult Intelligence Scale Digit Span subtest are based on identification of performance patterns that are implausible if the test taker is investing full effort. No studies to date, however, have examined the specificity of such measures, particularly when evaluating persons with either known or suspected learning or attention disorders. This study investigated performance of academically challenged students on three measures embedded in the Wechsler Adult Intelligence Scale-III, namely, low Digit Span, high Vocabulary-Digit span (Voc-DS), and low Reliable Digit Span scores. Evaluating subjects believed to be investing full effort in testing, it was found that both Digit Span and Reliable Digit Span had high specificity, although both showed relatively lower sensitivity. In contrast, VOC-DS was especially weak in both sensitivity and specificity, with an apparent false positive rate of 28%. Use of VOC-DS is therefore not appropriate for those with a history of learning or attention problems.