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Pediatric bipolar spectrum disorder and ADHD: comparison and comorbidity in the LAMS clinical sample


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Corresponding author:
L. Eugene Arnold, M.D.
Division of Child and Adolescent Psychiatry
Department of Psychiatry
Ohio State University
1670 Upham Drive
Columbus, OH 43210, USA
Fax: 614-688-5705


Arnold LE, Demeter C, Mount K, Frazier TW, Youngstrom EA, Fristad M, Birmaher B, Findling RL, Horwitz SM, Kowatch R, Axelson DA. Pediatric bipolar spectrum disorder and ADHD: comparison and comorbidity in the LAMS clinical sample. Bipolar Disord 2011: 13: 509–521. © 2011 The Authors. Journal compilation © 2011 John Wiley & Sons A/S.

Objective:  To compare attention-deficit hyperactivity disorder (ADHD), bipolar spectrum disorders (BPSDs), and comorbidity in the Longitudinal Assessment of Manic Symptoms (LAMS) study.

Methods:  Children ages 6–12 were recruited at first visit to clinics associated with four universities. A BPSD diagnosis required that the patient exhibit episodes. Four hypotheses were tested: (i) children with BPSD + ADHD would have a younger age of mood symptom onset than those with BPSD but no ADHD; (ii) children with BPSD + ADHD would have more severe ADHD and BPSD symptoms than those with only one disorder; (iii) global functioning would be more impaired in children with ADHD + BPSD than in children with either diagnosis alone; and (iv) the ADHD + BPSD group would have more additional diagnoses.

Results:  Of 707 children, 421 had ADHD alone, 45 had BPSD alone, 117 had both ADHD and BPSD, and 124 had neither. Comorbidity (16.5%) was slightly less than expected by chance (17.5%). Age of mood symptom onset was not different between the BPSD + ADHD group and the BPSD-alone group. Symptom severity increased and global functioning decreased with comorbidity. Comorbidity with other disorders was highest for the ADHD + BPSD group, but higher for the ADHD-alone than the BPSD-alone group. Children with BPSD were four times as likely to be hospitalized (22%) as children with ADHD alone.

Conclusions:  The high rate of BPSD in ADHD reported by some authors may be better explained as a high rate of both disorders in child outpatient settings rather than ADHD being a risk factor for BPSD. Co-occurrence of the two disorders is associated with poorer global functioning, greater symptom severity, and more additional comorbidity than for either single disorder.