ADHD adults (N = 26) were compared to normal controls
(N = 26) on 6 neuropsychological measures believed sensitive
to frontal lobe–executive functioning. MANOVA analyses
and subsequent univariate tests indicated that most of
the neuropsychological measures discriminated between the
two groups. To address clinical significance, diagnostic
classification rates were also generated for each measure
individually, and for the battery as a whole. Levels of
positive predictive power (PPP) for each of the 6 measures
(83–100%) indicated that abnormal scores on these
tests were good predictors of ADHD. However, estimates
of negative predictive power (NPP) suggested that normal
scores poorly predicted the absence of ADHD. When classification
rates were calculated for the overall battery classification
accuracy improved substantially. Thus, neuropsychological
tests can differentiate adults suffering from ADHD from
adults without ADHD, while also providing good classification
accuracy. Finally, the pattern of neurobehavioral impairments
exemplified through the Summary Index scores was interpreted
as consistent with conceptualizations of ADHD depicting
mild neurologic dysfunction in networks associated with
the frontal lobes. (JINS, 1999, 5, 222–233.)