Prevalence of attention deficit hyperactivity disorder in schoolchildren in the city of Salvador, Bahia, Brazil

background: attention deficit hyperactivity disorder (adhd) is the most common neuropsychiatric disorder of infancy and one of the most prevalent chronic diseases found in schoolchildren. objective: to evaluate the prevalence of adhd in schoolchildren through the use of a questionnaire responded by school-teachers. method: a total of 774 children enrolled in the public and private school systems were evaluated. the diagnostic instrument used was a teacher adhd scale. results: results showed that 6.7% of children were considered highly likely to have the disorder. of the more severe cases of adhd, the hyperactive-impulsive subtype was more frequently identified in girls, while the inattentive subtype was more prevalent among boys. conclusion: the symptoms of attention deficit in hyperactive children may be underestimated by teachers since the symptoms of hyperactivity are more noticeable and disruptive.