Browsing by Author "Butcher, Andrew Timothy"

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    Laboratory-based tasks in the diagnosis of ADHD in adults: a theoretical and empirical analysis
    Butcher, Andrew Timothy (Virginia Tech, 1996-05-04)
    The purpose of this study was to empirically evaluate the diagnostic utility of the Conners CPT and the P ASAT as a laboratory-based measures of attention, vigilance, working memory, and sustained mental effort in clinic-referred adults with and without ADHD. Moreover, the study was conducted in order to obtain additional evidence in ongoing efforts to clarify the classification and phenomenological status of ADHD in adults. Subjects were adults seeking psychological evaluation for a variety of presenting problems including, emotional, occupational, relational, and/or adjustment, difficulties. Standardized clinical evaluations were conducted and structured clinical interviews were used to determine clinical diagnosis and group membership (ADHD vs. Non-ADHD). It was hypothesized that ADHD adults would exhibit significantly more comorbid psychopathology, learning problems, and verbal memory deficits than non-ADHD adults. It was also hypothesized that the findings from the CPT (Conners, 1992) and P ASAT (Gronwall, 1977) would reliably discriminate these groups (ADHD and non-ADHD) of clinic-referred adults. While ADHD adults did not exhibit a higher frequency of learning disabilities, they did have significantly more comorbid psychopathology and were much more likely to experience clinically impairing deficits in verbal memory functioning. The combined results of the laboratory tasks accurately identified diagnostic group status in over 9 of 10 cases for ADHD adults and in approximately 8 of 10 cases for non-ADHD adults. The relevance of these findings for the psychiatric classification and experiential nature of ADHD in adults, as well as the clinical diagnostic utility of these laboratory measures for adult ADHD is discussed.
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    Symptom Dimensions and Neurocognitive Functioning in Adult ADHD
    Butcher, Andrew Timothy (Virginia Tech, 2000-07-13)
    Ongoing controversies regarding the clinical and nosological status of ADHD in adults emphasize the need for studies examining whether DSM-IV ADHD symptom dimensions and subtypes identified in research with children are valid for adults. Firm symptom criteria validated by data from adult samples have not been developed. Moreover, many clinic-referred adults present with attentional complaints and exhibit symptoms, neurocognitive weaknesses, and secondary problems similar to those seen in ADHD. However, data are mixed regarding the profile of neurocognitive deficits involved in adult expressions of ADHD, and it is unknown whether patterns of weakness in neurocognitive performance can be identified that reliably discriminate adults with ADHD from those with other neurobehavioral disorders (e.g., learning disabilities, LD). The purpose of this study was to further (a) evaluate the discriminant validity of DSM-IV ADHD in adults, (b) examine the nature and severity of neurocognitive deficits in adult ADHD, and (c) clarify the diagnostic utility of executive functioning measures among clinic-referred adults. Overall, results supported the discriminant validity of adult ADHD, but little support emerged for the existence of separate DSM-IV subtypes. Importantly, symptom ratings supported the existence of two broad symptom domains consistent with those delineated in DSM-IV. Moreover, principal components analysis of neuropsychological data identified three dimensions of neurocognitive executive functioning (EF; verbal working memory; sustained intention; and effortful learning) in which ADHD adults (n=35) performed significantly less well than those who received an LD diagnosis (n=24) or no diagnosis (n=21). Furthermore, composite scores in these EF domains generated correct classifications that were significantly better than chance when classifying adults that (a) did and did not meet criteria for ADHD, (b) met criteria for ADHD or LD, and (c) met criteria for ADHD or no clinical diagnosis. Classification results were robust when submitted to a jackknife (leave-one-out) validation procedure. Finally, results provided general support for the developmental lag hypothesis of frontal-subcortical functioning in ADHD when considered vis-à-vis child ADHD data, but findings also supported the notion that ADHD in adults is associated with continuing dysfunction in specific neuroanatomical pathways believed to subserve executive attentional functions (e.g., dorsolateral prefrontal-subcortical; anterior cingulate-subcortical; orbitofrontal-subcortical).