Characterizing impaired driving in adults with attention-deficit/hyperactivity disorder: A controlled study.

OBJECTIVE: We sought to confirm previously documented findings that individuals with attention-deficit/hyperactivity disorder (ADHD) demonstrate impaired driving behavior when compared with controls.

METHOD: Subjects were adults with (N = 26) and without (N = 23) DSM-IV ADHD ascertained through clinical referrals to an adult ADHD program and through advertisements in the local media. Driving behavior was assessed using the Manchester Driving Behavior Questionnaire (DBQ) and 10 questions from a driving history questionnaire. Neuropsychological testing and structured interviews were also administered to all subjects.

RESULTS: Substantially more ADHD subjects had been in an accident on the highway (35% vs. 9%, p = .03) or had been rear-ended (50% vs. 17%, p = .02) compared with controls. Analysis of the DBQ findings showed that ADHD subjects had significantly higher mean +/- SD scores than control subjects on the total DBQ (34.1 +/- 15.2 vs. 18.0 +/- 8.6, p < .001) and in all 3 subscales of the DBQ: errors (9.3 +/- 5.4 vs. 4.6 +/- 3.5, p < .001), lapses (12.4 +/- 6.2 vs. 6.1 +/- 3.5, p < .001), and violations (12.4 +/- 5.2 vs. 7.4 +/- 4.1, p < .001). Using the score that separated ADHD from control drivers on the DBQ as a cutoff, ADHD drivers at high risk for poor driving outcomes had more severe rates of comorbidity and exhibited more impaired scores on neuropsychological testing.

CONCLUSIONS: Our results confirm and extend previous work documenting impaired driving behavior in subjects with ADHD. Results also suggest that ADHD individuals at high risk for poor driving behavior might be distinguishable from other ADHD individuals on DBQ scores, neuropsychological deficits, and patterns of comorbidities.