The effectiveness of cognitive therapy on mindfulness on cognitive dissociation syndrome, inhibitory control, and behavioral problems in children with symptoms on the verge of attention deficit/hyperactivity disorder.

Studying the prevalence of subthreshold symptoms of attention deficit/hyperactivity disorder in Iranian children aged 8 to 13 years. Determining the effectiveness of mindfulness-based cognitive therapy (child version) on cognitive dissonance syndrome and on inhibitory control and behavioral problems in children with subthreshold symptoms of attention deficit/hyperactivity disorder.

This study was designed as a randomized, controlled, parallel-group clinical trial involving 80 patients. Random allocation was performed using the RAND function in Microsoft Excel."

Two sessions (each 45 min) were chosen and will be held in the Hamedan Province School Counseling Room every week. Accordingly, 24 sessions of 45 min will be held during the same 12 weeks. During the implementation of mindfulness-based cognitive therapy - child version, the treatment sessions will be repeatedly reviewed by the supervisors and counselors. Also, the content of the sessions will be recorded randomly and monitored by the supervising clinical psychologist with continuous feedback to the facilitator.

Age 10-13 years Willingness of the child to participate in the study Absence of chronic psychiatric disorders (schizophrenia spectrum, bipolar spectrum, and neurotic disorders). Receive a diagnosis of subthreshold symptoms of attention deficit/hyperactivity disorder by a clinical psychologist or psychiatrist with at least 5

1: will receive mindfulness-based cognitive therapy (child version). 2: will receive a mindfulness framework without mindfulness content.

Child and Adolescent Mindfulness Questionnaire The Child and Adolescent Behavioral Problems Scale was used to measure externalizing symptoms. Cognitive Dissociation Syndrome Inhibitory Control

The study was initially designed as a **crossover randomized controlled trial (RCT)** because this design has been employed in certain intervention studies to enhance statistical efficiency, reduce inter-individual variability, and ensure that all participants eventually receive the intervention. However, following a more thorough methodological review and expert feedback on the design of pediatric psychological trials, it became evident that a crossover design presents important limitations for mindfulness-based interventions, particularly **Mindfulness-Based Cognitive Therapy for Children (MBCT-C)**. A fundamental assumption of a crossover design is that the effects of the intervention are reversible or can be eliminated after the treatment phase, allowing participants to return to their baseline state following an adequate washout period. This assumption is not applicable to MBCT-C, as the intervention is specifically intended to produce enduring improvements in attentional regulation, emotional awareness, self-regulation, and behavioral control. The skills acquired during treatment are expected to persist beyond the intervention period and may even become further consolidated over time. Consequently, the likelihood of **carryover effects** is substantial, making it difficult to interpret post-crossover comparisons and potentially compromising the internal validity of the study. Accordingly, the study design was revised to a **parallel-group randomized controlled trial**. In this design, participants remain in their originally assigned groups following randomization, and the effectiveness of MBCT-C is evaluated by comparing the intervention group with the waitlist control group at the post-intervention assessment. This approach enables a clearer and more valid evaluation of the intervention by eliminating the risk of contamination resulting from prior exposure to treatment. Furthermore, adopting a parallel-group design simplifies the statistical analysis by eliminating the need to model **sequence effects**, **period effects**, and **carryover effects**, thereby improving the clarity and interpretability of the analytical strategy. This modification is also more consistent with the theoretical and clinical foundations of MBCT-C, in which the maintenance and consolidation of learned mindfulness skills are considered integral components of the therapeutic mechanism rather than factors that can be fully removed or controlled. Therefore, from both methodological and clinical perspectives, a parallel-group randomized controlled trial represents a more appropriate and scientifically rigorous design for evaluating the effectiveness of MBCT-C.

80 children will be randomly selected from the eligible participants. Their selection will be based on the number assigned to each child and will be done using the random number function in Excel. They will then be divided into groups one and two.