Prevalence of Pure Cognitive Disengagement Syndrome Without Co-Occurring ADHD in an Elementary School Sample of Children: A Two-Stage Epidemiological Study.

Cognitive disengagement syndrome (CDS), previously termed sluggish cognitive tempo, is characterized by excessive daydreaming, mental fogginess, slowed behavior, and low energy. Despite growing interest, epidemiological evidence-particularly for CDS without attention-deficit/hyperactivity disorder (ADHD)-remains limited. This study aimed to estimate the prevalence and correlates of CDS in a community sample of elementary school children using a two-stage epidemiological design. Children in Grades 2-4 from public schools in İzmir, Türkiye, were screened using parent- and teacher-reported measures (n = 366). Screen-positive cases underwent diagnostic evaluation with K-SADS-PL and clinical interviews. In the screening stage, CDS prevalence ranged from 5.4% to 15.0% depending on informant and impairment criteria. However, following the best-estimate diagnostic procedure, only four children (1.1% of the screened sample) met criteria for CDS without ADHD, corresponding to 25% of children initially identified as having CDS without ADHD during the screening phase. CDS symptom severity was positively associated with inattention and speech delay and negatively associated with hyperactivity. Findings highlight the importance of multi-stage assessment and support CDS as a potentially distinct clinical construct. To our knowledge, this is the first epidemiological study to apply a two-stage best-estimate procedure incorporating semi-structured and clinical interviews.