Examining the comorbidity of ADHD-related behaviours and conduct problems using a twin study design
Open Access
- 1 September 2001
- journal article
- research article
- Published by Royal College of Psychiatrists in The British Journal of Psychiatry
- Vol. 179 (3) , 224-229
- https://doi.org/10.1192/bjp.179.3.224
Abstract
Background: Although attention-deficit hyperactivity disorder (ADHD) and conduct disorder (CD) frequently co-occur, the underlying mechanisms for this comorbidity are not well understood.Aims: To examine whether ADHD and conduct problems share common risk factors and whether ADHD+CD is a more heritable variant of ADHD.Method: Questionnaires were sent to 2846 families. Parent-rated data were obtained for 2082 twin pairs and analysed using bivariate genetic analysis and a liability threshold model approach.Results: The overlap of ADHD and conduct problems was explained by common genetic and non-shared environmental factors influencing both categories. Nevertheless, the two categories appeared to be partly distinct in that additional environmental factors influenced conduct problems. It appeared that ADHD+CD was a genetically more severe variant of ADHD.Conclusions: Conduct problems and ADHD share a common genetic aetiology; ADHD+CD appears to be a more severe subtype in terms of genetic loading as well as clinical severity.Keywords
This publication has 18 references indexed in Scilit:
- Does the Definition of ADHD Affect Heritability?Journal of the American Academy of Child & Adolescent Psychiatry, 2000
- Toward guidelines for pedigree selection in genetic studies of attention deficit hyperactivity disorderGenetic Epidemiology, 1999
- Familial Subtypes of Attention Deficit Hyperactivity Disorder: A 4-year Follow-up Study of Children from Antisocial-ADHD FamiliesJournal of Child Psychology and Psychiatry, 1998
- Genetic and Environmental Influences on the Covariation Between Hyperactivity and Conduct Disturbance in Juvenile TwinsJournal of Child Psychology and Psychiatry, 1996
- Evidence for a genetic etiology in hyperactivity in childrenBehavior Genetics, 1992
- Parent and Teacher Ratings of ADHD Symptoms: Psychometric Properties in a Community-Based SampleJournal of Clinical Child Psychology, 1991
- Separation of DSM-III attention deficit disorder and conduct disorder: evidence from a family-genetic study of American child psychiatric patientsPsychological Medicine, 1991
- The use of multiple thresholds and segregation analysis in analyzing the phenotypic heterogeneity of multifactorial traitsAnnals of Human Genetics, 1979
- Reliably Separating Identical From Fraternal TwinsArchives of General Psychiatry, 1975