Tics and psychiatric comorbidity in children and adolescents

This study examined comorbid psychiatric symptoms in a large, community-based sample of children and adolescents. The study sample comprised a total of 3006 school children: 413 preschool (3 to 5 years; 237 males, 176 females; mean age 4 years 2 months, SD 8 months), 1520 elementary school (5 to 12 years; 787 males, 733 females; mean age 8 years 2 months, SD 1 year 11 months), and 1073 secondary school children (12 to 18 years; 573 males, 500 females; mean age 14 years 4 months, SD 1 year 10 months), all of whom were attending regular education programs. Children were evaluated with a teacher-completed DSM-IV-referenced rating scale. The sample was divided into four groups: attention-deficit-hyperactivity disorder with tics (ADHD+tics), ADHD without tics (ADHD), tics without ADHD (T), and a comparison group i.e. neither ADHD nor tics (Non). The percentage of children with tic behaviors varied with age: preschool children (22.3%), elementary school children (7.8%), and adolescents (3.4%). Tic behaviors were more common in males than females, regardless of comorbid ADHD symptoms. For many psychiatric symptoms, screening prevalence rates were highest for the ADHD groups (ADHD+tics>ADHD>T>Non). However, obsessive-compulsive and simple and social phobia symptoms were more common in the groups with tic behavior. Findings for a community-based sample show many similarities with studies of clinically referred samples suggesting that teacher-completed ratings of DSM-IV symptoms may be a useful methodology for investigating the phenomenology of tic disorders.