Attention-deficit/hyperactivity disorder symptoms in preschool children: examining psychometric properties using item response theory.

Clear and empirically supported diagnostic symptoms are important for proper diagnosis and treatment of psychological disorders. Unfortunately, the symptoms of many disorders presented in the Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.; DSM-IV-TR; American Psychiatric Association, 2000) lack sufficient psychometric evaluation. In this study, an item response theory (IRT) analysis was applied to ratings of the 18 attention-deficit/hyperactivity disorder (ADHD) symptoms in 268 preschool children. Children (55% boys, 45% girls) in this sample ranged in age from 37 to 74 months; 80.4% were identified as African American, 15.1% as Caucasian, and 4.5% as other ethnicity. Dichotomous and polytomous scoring methods for rating ADHD symptoms were compared and psychometric properties of these symptoms were calculated. Symptom-level analyses revealed that, in general, the current symptoms provided useful information in diagnosing ADHD in preschool children; however, several symptoms provided redundant information and should be examined further.