A cross-sectional and longitudinal investigation of the external correlates of sluggish cognitive tempo and ADHD-inattention symptoms dimensions.

The objective was to determine if the external correlates of sluggish cognitive tempo (SCT) and ADHD-inattention (IN) dimensions were the same in cross-sectional and longitudinal analyses. Teachers and aides rated SCT, ADHD-IN, ADHD-hyperactivity/impulsivity (HI), oppositional defiant disorder (ODD), and depression along with academic impairment in 758 Spanish children (55 % boys) on three occasions (twice at the end of the first grade year [6-week separation] and then again 12-months later at the end of the second grade year). Three of eight SCT symptoms showed substantial loadings on the SCT factor and substantially higher loadings on the SCT factor than the ADHD-IN factor for teachers and aides at each assessment (seems drowsy, thinking is slow, and slow moving). Cross-sectional and longitudinal analyses yielded similar results with SCT and ADHD-IN factors having different and unique external correlates (higher scores on SCT predicted lower scores on ADHD-HI and ODD while higher scores on ADHD-IN predicted higher scores on ADHD-HI and ODD with SCT and ADHD-IN both uniquely predicting academic impairment and depression). Developmental and methodological reasons are discussed for the failure to find an inconsistent alertness SCT factor (daydreams, alertness fluctuates, absent-minded, loses train of though, and confused).