Bullying and attention-deficit- hyperactivity disorder in 10-year-olds in a Swedish community.

The association of attention-deficit-hyperactivity disorder (ADHD) with bullying in the peer group in school was studied in an entire population of 577 fourth graders (10-year-olds) in one municipality in Stockholm, Sweden. The schoolchildren were screened for ADHD in a two-step procedure that included Conners'ratings of behavioural problems: teacher and parent interviews in a first step; and a clinical assessment in the second. Information about bullying was collected from the children themselves in a classroom questionnaire. Five-hundred and sixteen children (89.4%; 252 females, 264 males), for whom there was information from all data sources, were included in the study population. Conners'ratings that were collected from parents early in first grade were available for 382 of these children. Hypotheses were tested by multivariate analyses with adjustment for sex and parental education. Pervasive ADHD was diagnosed in 9.5% (95% confidence interval [CI] 5.6-12.8) of the males and 1.6% (CI 0.1-3.1) of the females. ADHD was associated with bullying other students (adjusted odds ratios (OR) 3.8 [CI 2.0-7.2]) as well as being bullied (often, OR 10.8 [CI 4.0-29.0]; sometimes, OR 2.9 [CI 1.5-5.7]). Bullying other students in fourth grade was associated with high scores in parental reports of behavioural problems at entry into first grade, suggesting a causal link to the ADHD syndrome. Being bullied, on the other hand, was not linked to behavioural problems at school entry. This study demonstrates a connection between ADHD and bullying in the peer group at school. Evaluation and treatment strategies for ADHD need to include assessment and effective interventions for bullying. Evaluation of ADHD should be considered in children involved in bullying.