Impact of the impairment criterion in the diagnosis of adult ADHD: 33-year follow-up study of boys with ADHD.

Objective: To investigate the relationship between ADHD symptoms and impairment among adults diagnosed as having ADHD in childhood (ages 6-12).

Method: Clinicians blindly interviewed 121 White males; the mean age was 41 years across the sample. DSM-IV adult ADHD behaviors were systematically rated, and impairment resulting from symptoms was scored on a 5-point Likert-type scale.

Results: Correlations between degree of impairment and number of behaviors were high (r's = .83 to .85, p < .001). The impairment criterion had no effect on classifying any participants as having, or not having, adult ADHD. All participants who reported experiencing 5 or more inattention or hyperactive-impulsive behaviors as "often" or "very often" in adulthood were significantly impaired by their symptoms.

Conclusions: Contrary to results reported in children, there was a strong relationship between number of ADHD symptoms and degree of impairment. However, for several reasons (discussed in the article), it should not be concluded that the impairment criterion is superfluous.