[Retrospective analysis of pervasive developmental disorder patients initially diagnosed with attention...

We retrospectively analyzed 66 patients with pervasive developmental disorder (PDD) whose respective diagnoses had been changed from attention deficit/hyperactivity disorder (AD/HD) and compared their clinical characteristics with those in patients whose diagnoses was not altered (n = 135). Of 52 patients, 41 (79%) had language delay or hyperactivity at initial examination. Of the 47 patients treated with methylphenidate, 41 patients (87%) responded favorably. The patients with altered diagnoses were categorized into three groups with inappropriate diagnoses (n = 32), amended diagnoses (n = 6), and dual diagnoses (n = 28). Consequently, some patients increasingly showed PDD characteristics concomitantly with age; other patients had justified dual diagnoses with PDD and AD/HD. The total points for peculiar behavioral history were significantly higher in patients with altered diagnoses than in those with unaltered diagnoses (5.4 +/- 3.7 vs. 2.6 +/- 2.6, p < 0.001). In particular, the points for language delay, indifference, and persistence were significantly more positive in patients with altered diagnoses. Results suggest that close evaluation of an individual's behavioral history might suggest a differential diagnosis between PDD and AD/HD.