This study aims to investigate the predictive and mediating relationships between emotion dysregulation, internalizing disorders, family functionality, loneliness preference, and executive functions (EF) in children with attention deficit hyperactivity disorder and cognitive disengagement syndrome (ADHD + CDS). This study included 176 children and adolescents (92 boys, 84 girls) who were diagnosed with ADHD + CDS according to the Diagnostic and Statistical Manual of Mental Disorders, the Fifth Edition criteria by a fellowship-trained child and adolescent psychiatrist, between ages 8 -12 (M = 10, SD = 1.52) with a convenience sampling method. The solitude scale for children, difficulties in emotion dysregulation scale, Child Behavior Checklist, Barkley Sluggish Cognitive Tempo Scale, Family assessment device, and CNS Vital Signs test were used. The results showed that difficulty in emotion regulation, preference for loneliness, internalizing disorders and CDS symptom severity did not have a mediating effect between family functionality and EF. Still, emotion dysregulation mediates the relationship between EF and internalizing disorders by itself and through loneliness preference. Also, preference for loneliness and emotion dysregulation had a mediating effect between family functionality and internalizing disorders. Finally, it was found that the effect of emotion regulation difficulty, loneliness preference, and internalizing disorders had a mediating role between CDS symptom severity and family functionality. In conclusion, the information obtained from this study on the etiology of CDS may guide future studies.