Genetic overlap between measures of hyperactivity/inattention and mood in children and adolescents.
OBJECTIVE
Evidence suggests that there is substantial comorbidity between attention-deficit/hyperactivity disorder (ADHD) and major depressive disorder in childhood and adolescence. This study aims to investigate the degree to which etiological factors are shared between the symptoms of these significantly heritable disorders.


METHODS
A twin study design was used to determine to what extent the covariation between the traits of ADHD and depression is genetically or environmentally mediated, based on parental reports. A general community sample of 645 twin pairs aged 5 to 17 years from the Cardiff Study of All Wales and North England Twins project took part in the study. Parent-rated measures of hyperactivity/inattention (Abbreviated Conners Hyperactivity subscale) and depression (Short Mood and Feelings Questionnaire).


RESULTS
Phenotypes derived from the scales were significantly correlated in both boys and girls. Bivariate structural equation modeling revealed a large overlap in underlying genetic factors (boys, rA = 0.77; girls, rA = 0.67) along with a smaller influence of nonshared environment.


CONCLUSIONS
These findings suggest that there are common genes conferring liability to both hyperactive/inattentive and depressive traits in children and adolescents. This has implications for future molecular genetic research into ADHD and major depressive disorder. Additionally, it indicates that the comorbid clinical presentation of these disorders may reflect a common genetic pathway.
Mr. Cole, Drs. Ball, and McGuffin are with the Social, Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry; Dr. Martin is with the School of Psychology, Curtin University; and Dr. Scourfield is with the Department of Psychological Medicine, University of Wales College of Medicine. Electronic address: james.cole@iop.kcl.ac.uk.
James
J
Cole
Mr. Cole, Drs. Ball, and McGuffin are with the Social, Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry; Dr. Martin is with the School of Psychology, Curtin University; and Dr. Scourfield is with the Department of Psychological Medicine, University of Wales College of Medicine.
Harriet A
HA
Ball
Mr. Cole, Drs. Ball, and McGuffin are with the Social, Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry; Dr. Martin is with the School of Psychology, Curtin University; and Dr. Scourfield is with the Department of Psychological Medicine, University of Wales College of Medicine.
Neilson C
NC
Martin
Mr. Cole, Drs. Ball, and McGuffin are with the Social, Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry; Dr. Martin is with the School of Psychology, Curtin University; and Dr. Scourfield is with the Department of Psychological Medicine, University of Wales College of Medicine.
Jane
J
Scourfield
Mr. Cole, Drs. Ball, and McGuffin are with the Social, Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry; Dr. Martin is with the School of Psychology, Curtin University; and Dr. Scourfield is with the Department of Psychological Medicine, University of Wales College of Medicine.
Peter
P
Mcguffin
D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology; D004200:Diseases in Twins / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology; D004739:England; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005838:Genotype; D006801:Humans; D008297:Male; D010552:Personality Assessment; D010641:Phenotype; D012307:Risk Factors; D012737:Sex Factors; D012931:Social Environment; D014852:Wales