Factor and latent class analysis of DSM-IV ADHD symptoms in a school sample of Brazilian adolescents

Objective: To evaluate the validity of the multidimensional construct proposed by DSM-IV for the diagnosis of attention-deficit/hyperactivity disorder (ADHD) in a school sample of young Brazilian adolescents. Method: An instrument including all 18 DSM-IVADHD symptoms was administered to 1,013 students aged 12 to 14 years at 64 state schools by trained research assistants. Each symptom was rated on a Likert scale with five levels of severity (never, almost never, sometimes, frequently, and always). Results: Using an exploratory factor analytic approach (principal components analysis), two factors were extracted. Factor I (hyperactivity-impulsivity) comprised eight DSM-IV hyperactive-impulsive symptoms with loadings greater than or equal to0.40. Factor ii (inattention) included also eight DSM-IV symptoms of inattention. The two factors explained 34% of the total variance and had an interfactor correlation of 0.45. Latent class analysis demonstrated similar classes in males and females, but class structures were markedly different from previous analyses of parent report data. Conclusion: The findings support the appropriateness of the multidimensional construct introduced by DSM-IV in the diagnosis of ADHD in a different culture but emphasize the possible impact of different reporters on the results of structural model-testing.