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Most studies of psychiatric problems in children with tics have included only children referred to clinics. There have been few community based studies and those that have been reported have used parent reports the validity of which has been questioned. The association between tics, attention-deficit-hyperactivity disorder (ADHD), and psychiatric symptoms has been investigated using teacher reports in three areas of the United States (Missouri, Wisconsin, and Long Island, New York) (
The study included 3006 children: 413 preschool (age 3–5 years, attending private preschool and day care centres or Head Start programmes, 237 boys), 1520 elementary school (age 5–12 years, 787 boys), and 1073 secondary school (age 12–18 years, 573 boys). They were assessed by teachers using a Diagnostic and Statistical Manual of Mental disorders 4th edition (DSM-IV)-referenced behaviour rating scale appropriate to age. Children were divided into four groups: ADHD with tics (128), ADHD without tics (220), tics without ADHD (125), and neither tics nor ADHD (2533).
The prevalence of tics, with or without ADHD, decreased with age (preschool 22%, elementary school 8%, secondary school 3%). Both tics and ADHD were more common in boys at all ages. Most psychiatric symptoms (including oppositional defiant disorder, conduct disorder, and generalised anxiety disorder) were most prevalent in children with ADHD (ADHD + tics >ADHD alone > tics alone > neither) but obsessive-compulsive disorder and phobias were most prevalent in children with tics.
Tics are common in preschool children and become less common as childhood progresses. Most psychiatric symptoms have a greater association with ADHD than with tics but obsessive-compulsive disorder and phobias have a greater association with tics than with ADHD.