Introduction
Sluggish cognitive tempo (SCT), recently known as cognitive disengagement syndrome (CDS), is a relatively new clinical construct that refers to a set of cognitive and behavioral symptoms including lethargy, daydreaming, drowsiness, being easily confused, and slow thinking and responding. Most initial studies on SCT had focused on the empirical distinction between SCT and the inattentive type of attention deficit/hyperactivity disorder (ADHD). Following the emergence of additional evidence highlighting the differences between SCT and ADHD, researchers increasingly investigated the causes, correlates, and consequences of SCT. Their findings indicated that SCT is significantly linked to ADHD, sleep problems, executive functioning problems (particularly in metacognitive areas such as planning and organization), and symptoms of autism spectrum disorder (ASD). Most SCT studies have been conducted on ADHD samples and the general population, while SCT is prevalent among children with ASD. Few studies have explored the relationship between SCT and other symptoms in ASD children. In Iran, there has been no research on SCT in children with ASD. Therefore, this study aims to investigate the ADHD symptoms, sleep problems, and executive functions as predictors of SCT in Iranian children with high-functioning ASD.

Method
This is a descriptive-correlational study. The participants were the parents of 122 children aged 6-12 with high-functioning ASD selected from specialized autism schools in Tehran, Iran. Data was collected using the convenience sampling method from January to February 2024. The parents who scored 55-70 in the Gilliam Autism rating scale-third edition and had a score above the cut-off point on the SCT scale were selected. They completed the online forms of the Swanson, Nolan, and Pelham rating scale (SNAP-IV), the children’s sleep habits questionnaire (CSHQ), and the coolidge personality and neuropsychological inventory for children (CPNI). 
The SPSS software, version 27 was used for data analysis. The Shapiro-Wilk test was first employed to assess the normality of data distribution. Pearson’s correlation test was then used to calculate the correlation between the variables. Finally, multiple regression analysis was used to find the predictors. The significance level was set at 0.05.

Results
The final analysis was conducted on the parents of 116 children. Since the skewness and kurtosis values for all variables fall within the range of -2 to 2, the distributions were considered normal. Furthermore, the Shapiro-Wilk test results showed all variables had a normal distribution (P>0.05).
The results in Table 1 indicated that SCT, as the criterion variable, had a positive and significant association with three variables: Inattention, decision-making/planning, and organizing.


The SCT had no significant relationship with the variables of sleep problems, hyperactivity, and response inhibition. Consequently, sleep problems, hyperactivity, and response inhibition were excluded from the regression model. The regression analysis results indicated that only inattention had a significant predictive power and was significantly correlated with SCT (P<0.05, r=0.489). In this model, the coefficient of determination was 0.23, indicating that inattention accounts for 0.23 of the variance in the SCT variable (Table 2).



Conclusion 
The SCT is not correlated with sleep problems in children with high-functioning ASD. However, this finding remains controversial and requires further investigation. The second finding of the study is that SCT has a positive and significant correlation with the inattentive symptom of ADHD in these children, but not with the hyperactive symptom of ADHD. The inattentive symptom is a significant predictor of SCT in children with ASD. Given the overlap of symptoms between SCT and inattention and the high co-occurrence of ADHD in children with ASD, it is reasonable to expect a significant relationship between SCT and inattention in children with ASD. The third finding is that SCT has a positive and significant correlation with decision-making and organizing skills of children with ASD, but has no significant relationship with the response inhibition skill. Given the characteristics of children with SCT symptoms, such as daydreaming, being easily confused, slow thinking and responding, and a lack of constant vigilance, it is expected that these children experience difficulties with executive functions, including working memory, planning, and organization. The findings of this study offer comprehensive insights into the variables associated with SCT in children with ASD. This information can enhance the knowledge of parents, professionals, and therapists who work with and provide services for this group of children.

Ethical Considerations
Compliance with ethical guidelines
This study was approved by the Ethics Committees of the University of Social Welfare and Rehabilitation Sciences (Code: IR.USWR.REC.1402.196). Written informed consent was obtained from all parents before the study. Their information was kept confidential.

Funding
This article was extracted from the master's thesis of Kosar Razavi at the Department of Psychology and Education of Exceptional Children, University of Social Welfare and Rehabilitation Sciences. This research did not receive any grant from funding agencies in the public, commercial, or non-profit sectors.

Authors contributions
Conceptualization, review & editing: Marjan Poshtmashhadi, Masoume Pourmohamadreza-Tajrishi, and Kosar Razavi; Methodology and validation: All authors; data analysis: Marjan Poshtmashhadi, Kosar Razavi, and Razie Bidhendi Yarandi; investigation, writing initial draft: Kosar Razavi; Supervision: Marjan Poshtmashhadi, Masoume Pourmohamadreza-Tajrishi, and Razie Bidhendi Yarandi.

Conflicts of interest
The authors declared no conflict of interest.

Acknowledgments
The authors would like to thank the Exceptional Education Organization in Tehran and all children and parents for their cooperation in this research.



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