Clinical distinction between cognitive disengagement syndrome and ADHD presentations in a nationally representative sample of Spanish children and adolescents

Background This study sought to determine whether cognitive disengagement syndrome (CDS, formerly sluggish cognitive tempo) has different external correlates relative to ADHD‐inattentive presentation (INP), ADHD‐hyperactive/impulsive presentation (HIP), and ADHD‐combined presentation (CP). Methods Parents of a nationally representative sample of 5,525 Spanish youth (ages: 5–16, 56.1% boys) completed measures of CDS, ADHD‐inattention (IN), and ADHD‐hyperactivity/impulsivity (HI) and other measures. Scores greater/less than the top 5% on CDS, ADHD‐IN, and ADHD‐HI were used to create control (n = 5,013, 90.73%), CDS‐only (n = 131, 2.37%), ADHD‐INP‐only (n = 83, 1.50%), ADHD‐HIP‐only (n = 113, 2.05%), ADHD‐CP‐only (n = 48, 0.97%), CDS + ADHD‐INP (n = 44, 0.80%), CDS + ADHD‐HIP (n = 25, 0.45%), and CDS + ADHD‐CP (n = 68, 1.23%) groups. Results Forty‐nine percent of youth with clinically elevated CDS did not qualify for any ADHD presentation, whereas 64% of youth with clinically elevated ADHD did not qualify for CDS. The CDS‐only group was higher than the ADHD‐INP‐only, ADHD‐HIP‐only, and ADHD‐CP‐only groups on anxiety, depression, somatization, daytime sleep‐related impairment, nighttime sleep disturbance, and peer withdrawal, whereas the CDS‐only and ADHD‐INP‐only groups did not differ on ODD (ADHD‐HIP‐only and ADHD‐CP‐only higher) and academic impairment (ADHD‐CP‐only higher than CDS‐only and ADHD‐HIP‐only lower than CDS‐only). The CDS‐only group also had higher rates of anxiety, depression, and bipolar disorder diagnoses than the ADHD‐only group. Conclusions A distinction was found between CDS and each ADHD presentation, thus providing support for CDS as a syndrome that frequently co‐occurs with yet is distinct from each ADHD presentation.