Objective: Sleep disturbance is considered both a behavioral symptom of and a contributor to functional difficulties in children with attention-deficit/hyperactivity disorder (ADHD). The construct of sluggish cognitive tempo (SCT) has also been linked to ADHD; however, little is known regarding the effects of sleep specifically on SCT symptoms. This study examined the association between parent-reported sleep disturbance and parent- and teacher-reported SCT, while controlling for the effects of ADHD and mood symptoms.
Method: Participants included 746 clinically referred children (65% male, age range: 5-18 years) with both parent and teacher ratings assessing symptoms of ADHD, mood symptoms (depression, anxiety), and SCT. Parents/caregivers also rated their child's sleep problems with regard to 4 core concerns: falling asleep, sleep restlessness, difficulty waking, and breathing difficulties. The SCT scale included three empirically derived subscales: sleepy/sluggish, low initiation/persistence, and daydreamy.
Results: After accounting for age, medication status, ADHD symptoms, depressive symptoms, and anxiety, sleep problems accounted for a small but significant proportion of additional variance in the prediction of parent-reported sleepy/sluggish SCT. Difficulty waking showed the strongest associations with parent-reported SCT. There were no significant relationships found between parent-reported sleep difficulties and teacher-reported SCT.
Conclusions: Some elements of sluggishness and lethargy inherent to the SCT construct may be associated with sleep difficulties, even after accounting for ADHD and mood symptoms; however, these associations are not consistent across SCT subscales and sleep problem domains.