TWIN-SIBLING DIFFERENCES IN PARENTAL REPORTS OF ADHD, SPEECH, READINGAND BEHAVIOR PROBLEMS

Differences between twins and siblings in behaviour problems were inve stigated in a nonselected sample of 1938 families with children aged 4 -12 years. Families were sent a questionnaire based on DSM-III-R crite ria for Attention Deficit Hyperactivity Disorder (ADHD), Oppositional Defiant Disorder (ODD), Conduct Disorder (CD) and Separation Anxiety ( SA), which was validated by formal clinical interview. The questionnai re also included measures of speech and reading problems. There were s ignificant differences between twins and siblings for ADHD symptoms, b ut not for symptoms of ODD, CD or SA. Twins and siblings differed sign ificantly for gestational age, birth weight, speech and reading proble ms. While there was little evidence for birth weight or gestational ag e contributing to the difference in ADHD symptoms, there was a strong association between ADHD symptoms and speech and reading problems. Cop yright (C) 1996 Association for Child Psychology and Psychiatry.