Journal of Affective Disorders 51 (1998) 101–112 Research report Clinical features of children with both ADHD and mania: does ascertainment source make a difference? a, a a a * Joseph Biederman , Ronald Russell , Jennifer Soriano , Janet Wozniak , Stephen a ,b V. Faraone a Pediatric Psychopharmacology Unit of the Child Psychiatry Service, Massachusetts General Hospital, ACC 725, MGH, Fruit Street, Boston, MA 02114, USA b Harvard Institute of Psychiatry Epidemiology and Genetics, Department of Psychiatry, Harvard Medical School at the Massachusetts Mental Health Center, and the Commonwealth Research Center, Boston, MA, USA Abstract Objective: We evaluated the structural diagnostic results of children ascertained through an ADHD diagnosis with comorbid mania to determine if they have the same phenotype as children ascertained through a mania diagnosis with comorbid ADHD. Method : We compared a sample of children participating in a family genetic study of ADHD to a sample of children ascertained through a study of childhood mania. Results: Similar correlates of ADHD and mania were observed in children satisfying criteria for both disorders irrespective of ascertainment source. Conclusions: Findings suggest that children with mania and ADHD have two disorders, their features not varying with the primary diagnostic focus. Limitations: The results may have been limited by small sample size. Clinical relevance: Because the coexistence of ADHD and mania seriously complicates the course and treatment of children, understanding the compatibility of these disorders has important clinical implications in the management of this population.  1998 Elsevier Science B.V. All rights reserved. Keywords: Bipolar disorder; ADHD; Comorbidity; Children; Adolescents 1. Introduction rates of ADHD (attention deficit hyperactivity disor- der) ranging from 57% to 98% (Geller et al., 1995; Despite controversy, it has been increasingly West et al., 1995; Wozniak et al., 1995a) and rates of recognized that a substantial minority of children bipolar disorder of up to 22% have been reported in suffer from a very severe form of psychopathology inpatient (Butler et al., 1995) and outpatient (Bieder- associated with extreme irritability, aggression, and man et al., 1996) samples of ADHD youth. incapacitation that has a clinical presentation con- In a series of articles, we documented a bi-direc- sistent with the diagnosis of mania. Systematic tional diagnostic overlap between ADHD and mania studies of manic children and adolescents have found in studies of children with mania and in studies of children with ADHD (Biederman et al., 1996, 1995; * Wozniak et al., 1995a,b). These findings could not be Corresponding author. Tel.: 1 1-617-726-1737, fax: 1 1-617- 724-1540. accounted for by the overlapping symptoms of 0165-0327 / 98 / $ – see front matter  1998 Elsevier Science B.V. All rights reserved. PII: S0165-0327(98)00177-3