Source
Department of Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA. faraones@upstate.edu
Abstract
BACKGROUND:
Diagnosing attention-deficit/hyperactivity disorder (ADHD) in adults is difficult when the diagnostician cannot establish an onset prior to the DSM-IV criterion of age 7 or if the number of symptoms recalled does not achieve the DSM-IV threshold for diagnosis. Because neuropsychological deficits are associated with ADHD, we addressed the validity of the DSM-IV age at onset and symptom threshold criteria by using neuropsychological test scores as external validators.
METHODS:
We compared four groups of adults: 1) full ADHD subjects met all DSM-IV criteria for childhood-onset ADHD; 2) late-onset ADHD subjects met all criteria except the age at onset criterion; 3) subthreshold ADHD subjects did not meet full symptom criteria; and 4) non-ADHD subjects did not meet any of the above criteria.
RESULTS:
Late-onset and full ADHD subjects had similar patterns of neuropsychological dysfunction. By comparison, subthreshold ADHD subjects showed few neuropsychological differences with non-ADHD subjects.
CONCLUSIONS:
Our results showing similar neuropsychological underpinning in subjects with late-onset ADHD suggest that the DSM-IV age at onset criterion may be too stringent. Our data also suggest that ADHD subjects who failed to ever meet the DSM-IV threshold for diagnosis have a milder form of the disorder.