Sluggish cognitive tempo predicts a different pattern of impairment in the attention deficit hyperactivity disorder, predominantly inattentive type.

Compared 2 groups of children with attention deficit hyperactivity disorder, predominantly inattentive type (ADHD/IA)--those with high scores on a composite measure of sluggish cognitive tempo (SCT) and those without--using a large, school-based sample of children for which previous comparisons between ADHD subtypes have been reported. Although the 2 groups did not differ on level of attention or learning problems, high-SCT ADHD/IA children were rated by teachers as showing less externalizing behavior and higher levels of unhappiness, anxiety/depression, withdrawn behavior, and social dysfunction. Thus, SCT identifies a more homogeneous subgroup of ADHD/IA children who are, relative to the entire Diagnostic and Statistical Manual of Mental Disorders (4th ed. [DSM-IV]; American Psychiatric Association [APA], 1994) diagnosed ADHD/IA group, more similar to those classified in previous research as "attention deficit disorder without hyperactivity." These results support a reconsideration of SCT symptoms as a component of diagnostic criteria for a category of nonhyperactive attention deficit disorder.