This study examined the latent structure and validity of inattention, hyperactivity-impulsivity, and sluggish cognitive tempo (SCT) symptomatology. We evaluated mother and teacher ratings of ADHD and SCT symptoms in 140 Puerto Rican children (55.7% males), ages 6 to 11 years, via factor and regression analyses. A three-factor model (inattention, hyperactivity-impulsivity, and SCT) provided the …