Emotion regulation refers to the process of adjusting various aspects of an emotional experience or response (Gross, 1998). Gross and Thompson (2007) describe five categories of effective emotion regulation strategies: situation selection, situation modification, attentional deployment, cognitive change, and response modulation. Effective emotion regulation helps keep the individual within a window of tolerance, allowing for optimal emotional functioning (Siegel, 1999; Greenberg, 2021). Therefore, emotion regulation is regarded as fundamental to mental health and adaptive psychological functioning. However, when emotion regulation fails or becomes ineffective, individuals may experience emotion dysregulation (ED). ED, indeed, occurs when there are deficits in adaptive regulation strategies or when ineffective responses are used, resulting in a mismatch between a person’s emotional expressions/experiences and the demands of the environment (Gross and Thompson, 2007). According to the distinction proposed by Cole et al. (2017) four types of dysregulated emotions associated with various forms of psychopathology can be identified. In the first case, emotions persist, and efforts to regulate them are unsuccessful (e.g., generalized anxiety and depression); in the second case, emotions disrupt appropriate behavior (e.g., disruptive behavior disorder). In the third case, emotions that are either expressed or felt are inappropriate for the context (e.g., posttraumatic stress disorder). Finally, emotions may shift either too rapidly or too gradually (e.g., bipolar disorder) (Cole et al., 2017). ED has been associated with poorer adaptive psychological and physical health outcomes, such as psychiatric symptoms, sleep disturbances and non-suicidal self-injury (Bradley et al., 2011; Wolff et al., 2019; Vanek et al., 2020).

Strategies of emotion regulation have been related with some neuropsychological correlates, such as language (Griffiths et al., 2021) working memory (Löytömäki et al., 2020) and cognitive abilities (Growney and English, 2023). Associations with disrupted sleep patterns have also been documented (Fisher et al., 2022). Since emotion regulation strategies often require complex cognitive skills, individuals with intellectual disability (ID) may be at higher risk of experiencing ED. For instance, in individuals with autism spectrum disorder and co-occurring ID, a mediating role of maladaptive emotion regulation strategies in relation to anxiety symptoms has been documented (Sáez-Suanes et al., 2020). A systematic review summarised the state of the art about ED in syndromic ID, reporting several studies that have suggested higher ED in individuals with ID [i.e., Down syndrome (DS), fragile X syndrome, tuberous sclerosis complex, Williams syndrome, Prader-Willi syndrome, and Angelman syndrome] in comparison with typically developing individuals (Shaffer et al., 2023). Some of these studies focused on DS, the most common genetic cause of ID. Challenging behaviors are common in youth with DS, with prevalence estimates reaching up to 100% (Mannion et al., 2024). Children and adolescents with DS may exhibit different kinds of behavioral issues depending on the developmental stage. Elevated levels of externalizing behaviors, such as impulsivity and temper tantrums, are frequently observed in early childhood and among school-aged children, whereas with maturation individuals with DS can experience higher rates of internalizing symptoms (Grieco et al., 2015). The systematic review by Shaffer et al. (2023) confirmed that individuals with DS exhibit ED, with inconsistent findings on potential sex differences and some evidence that behaviors related with ED tend to be stable among school-age children (Shaffer et al., 2023).

Despite the growing interest in investigating ED in individuals with ID, little is known about the neuropsychological and psychopathological profiles associated with ED in children and adolescents with DS. Thus, the current study had three aims:

By addressing these dimensions, the findings may contribute to the development of targeted interventions and support strategies aimed at improving the overall wellbeing and quality of life for this vulnerable population.

The first aim of the current work was to investigate whether the presence of ED in children and adolescents with DS is associated with a distinct neuropsychological profile (e.g., cognitive, linguistic and visual-motor integration skills) compared to peers with DS without ED. We did not find group differences in nonverbal cognitive abilities. Although the design of the present study does not allow causal inferences about the relationship between ED and cognitive level, it is noteworthy that our results align with previous findings showing that the nonverbal reasoning does not predict success on a recognition of emotional facial expressions task in youth with DS, in contrast to what has been observed in typically developing children (Pochon et al., 2017).

We also found that children with DS and co-occurring ED did not differ in language skills from children with DS without ED. To our knowledge, this is the first study to examine language abilities in children with DS and ED using a comparative approach. Although research in typically developing populations suggests links between expressive vocabulary, working memory, and emotion recognition (Löytömäki et al., 2020), such associations may not generalize to DS due to their unique cognitive and neurological profile, which can influence how emotional regulation is acquired and expressed, independently of language proficiency. Previous research on adults with DS indicates that structural language level may be involved in mentalistic aspects of emotion understanding (Andrés-Roqueta et al., 2021), which is essential for basic emotion regulation, supporting the understanding of mental components such as attributing correct desires, beliefs, or intentions in stories. Our findings contribute to this line of research by examining associations specifically with ED rather than with basic regulatory skills. However, it should be noted that the present study assessed only lexical production and comprehension. Moreover, it used age-equivalent scores from a preschool-normed test to assess linguistic abilities in older participants, which may limit external validity. Nonetheless, this method was necessary to avoid floor effects and to meaningfully capture the participant’s abilities in this specific clinical sample (Edgin et al., 2010; Edgin, 2013; Esbensen et al., 2024). Future studies on the clinical features associated with ED in children and adolescents with DS could benefit from including more sensitive instruments and measures of other aspects of language and communication skills, such as verbal fluency or the comprehension of emotional prosody.

Children in the DS + ED group exhibited significantly worse visual-motor integration and motor coordination abilities, as measured by the Beery VMI test. This finding provides further support for the observation by Shaffer et al. (2023), who highlighted that cerebellar and hippocampal dysfunctions, coupled with impaired synaptic activity, lead to difficulties in motor coordination, learning, and memory in DS. In particular, the cerebellum is involved not only in motor control but also in emotional and cognitive regulation (Adamaszek et al., 2017; Stoodley and Schmahmann, 2018). It contributes to several key components of emotion processing, including physiological responses that underlie the subjective experience of emotions, emotional expressions that support social communication, and cognitive appraisal processes that evaluate whether stimuli elicit emotions and of what type (Baumann and Mattingley, 2022). This is in line with the universal hypothesis of cerebellar functioning, which proposes that the cerebellum optimizes accuracy, consistency, and appropriateness across both cognitive and affective domains, similar to its role in motor control (Baumann and Mattingley, 2022). Therefore, atypical cerebellar functioning in DS may represent a shared neural substrate linking motor impairments and increased ED.

At the same time, environmental factors may amplify these vulnerabilities. Children with poor motor skills often encounter repeated failures in everyday activities, reduced participation in peer play, and higher levels of parental stress, which can increase the risk of frustration and negative emotionality (Pimenta et al., 2023). In this perspective, Shaffer et al. (2023) suggested that, in DS population, motor coordination difficulties may heighten the risk of encountering frustration, which in turn may trigger the expression of ED. This interpretation is consistent with the findings from a study by Jahromi et al. (2008), who reported that children with DS exhibit limited repertoire for coping with frustration. Evidence from other developmental conditions reinforces this view: for instance, research on children with developmental coordination disorder has documented a connection between motor coordination problems and increased susceptibility to emotional and behavioral difficulties, including challenges in self-regulation (Green and Payne, 2018). An explanatory framework for this association can be traced in the Elaborated Environmental Stress Hypothesis (Cairney et al., 2013), which posits that poor motor skills increase the risk of internalizing problems through interactions with environmental stressors that act as intermediaries. Future studies should take into account the potential influence of environmental stressors on the relationship between motor coordination difficulties and ED in youth with DS. Given that individuals with DS are more prone to motor difficulties (Alesi et al., 2022), investigating these factors would enable a better understanding of the complex interactions between motor skills, mental health, and environmental influences, ultimately informing more effective interventions for children at risk. However, it is important to underline that, due to the cross-sectional design of the present study, no causal inferences can be drawn regarding the direction of the association between motor difficulties and ED.

The second objective of the present study was to explore potential differences in the distribution of psychopathological symptoms between children with DS with or without ED. Given that group assignment was based on the CBCL-DP, which already captures elevated internalizing and externalizing problems, the presence of more psychopathological symptoms in the DS + ED group might partly be expected. For this reason, we analysed the K-SADS data to offer a more objective and clinically detailed assessment, complementing the CBCL-DP classification. The structured clinical interview allowed us to specify diagnostic categories and quantify their prevalence in each group. Compared to the DS − ED group, children in the DS + ED group showed substantially higher prevalence of ADHD (26.1% vs. 13%), oppositional defiant disorder (25% vs. 3%), mood disorders (5.8% vs. 2.1%), and anxiety disorders (11.6% vs. 4.8%), along with a markedly lower proportion with no diagnosable symptoms (27.5% vs. 68%). These results indicate that, in children with DS, ED is associated with a broad spectrum of psychopathology, involving not only externalizing disorders but also internalizing conditions. This finding confirms and extends to the DS population previous evidence that ED reflects a restricted range of ineffective strategies for understanding or accepting one’s emotions, together with a limited repertoire for managing them (Gratz and Roemer, 2004), making it a factor that is strongly associated with psychopathological symptoms also in youth with DS. The results of the present study highlight the importance of early identification and tailored interventions to address the mental health needs of children with DS and co-occurring ED. Notably, since the existing literature on ED in individuals with ID mostly focused on externalizing behaviors (Te Brinke et al., 2021; Mcclure et al., 2009; Shaffer et al., 2023), our study emphasises the need for a comprehensive approach that also addresses ED and internalizing issues in this population, particularly in youth with DS. Further research is essential to clarify the underlying mechanisms and to develop more effective, individualised treatment strategies for children with DS and ED. Our findings, indeed, underscore the importance of systematically integrating ED monitoring into routine DS care. Parental training programs could play a crucial role by equipping caregivers with strategies to identify early signs of ED, promote adaptive responses in everyday contexts, and reduce escalation into more severe behavioral or emotional problems. A recent randomised feasibility pilot clinical trial explored the feasibility and acceptability of a parent training protocol for disruptive behaviors specifically designed for caregivers of children with DS, reporting decreased externalising behaviors, irritability and hyperactivity and improved behavioral regulation in executive functioning over time (Stone-Heaberlin et al., 2024). Promising intervention options may also arise from research evaluating the applicability and effectiveness of existing interventions targeting ED in populations with ID, such as Dialectical Behavior Therapy (DBT), as suggested by preliminary evidence (Florez and Bethay, 2017; McNair et al., 2017). Typical modifications to DBT involve simplifying concepts and language, repeating key content, incorporating visual supports, and providing additional assistance to help participants complete therapy material (McNair et al., 2017). Adapting evidence-based protocols such as DBT to the specific cognitive and social profile of individuals with DS may offer additional benefits, particularly if combined with psychoeducational components for families and teachers. Such approaches may foster a more comprehensive care model, in which ED is recognised and addressed as a central clinical feature, ultimately improving both emotional wellbeing and overall quality of life for children with DS and their families.

The last aim of this study was to investigate whether children and adolescents with DS and ED experience more sleep problems than those without co-occurring ED. Our results indicate that youth in the DS + ED group exhibited more sleep disturbances than those in the DS− ED group, particularly with respect to insomnia and parasomnias. The relationship between sleep and ED has been investigated by several studies, which have shown, for instance, that sleep deprivation reduces individuals’ ability to manage intense emotional reactions to highly negative stimuli (Yoo et al., 2007) and affects behavioral inhibition (Harrison and Horne, 1998), decision-making, and impulsivity (Killgore et al., 2006). These sleep-induced changes may work together to hinder the regulation of behaviors and emotions. Consistently, a study conducted in a sample of 476 college students found that participants self-reporting good sleep reported also significantly less ED than participants reporting more sleep difficulties (Fisher et al., 2022). Of note, the relationship between sleep and ED is thought to be bidirectional, as affective states can influence sleep patterns in various ways, such as through stress (Kahn et al., 2013). Our results confirm and extend to DS paediatric population previous findings in both typically developing children (Lustig et al., 2021) and clinical populations such as autism spectrum disorder (Northrup et al., 2024) and ADHD (Sanabra et al., 2022). However, given the distinct behavioral phenotype of DS, parallels with findings from other populations should be interpreted with caution, and are mentioned here only to highlight a broader pattern rather than to imply direct equivalence. As suggested by literature, the connections between sleep and ED are probably reciprocal, where sleep issues or lack of sleep worsen emotional and behavioral challenges, and ED interferes with sleep patterns. It should be noted that the results of the current study contrast with previous research indicating that children with DS and obstructive sleep apnoea display greater difficulties in emotional control than those without obstructive sleep apnoea (Joyce et al., 2020). The discussion on this inconsistency should take into account that in Joyce et al.’s study, obstructive sleep apnoea was specifically assessed using cardiorespiratory polygraphy in children aged from 36 months to just under 6 years, whereas in our study sleep breathing disorders were evaluated only through a screening questionnaire and the age range of participants differed. These differences in assessment procedures and participant characteristics are likely to account, at least in part, for the contrasting findings.

Our findings have important implication for the treatment of children and adolescents with DS and co-occurring ED, highlighting the need to address both sleep problems and emotional difficulties in an integrated manner. Treatments should consider the bidirectional relationship between sleep and emotions, as improvements in sleep may lead to a reduction in emotional and behavioral symptoms, and vice versa. Interventions aimed at improving sleep quality, such as sleep hygiene management or the introduction of relaxation techniques, could have positive effects on ED as well. At the same time, interventions targeting emotion management could help improve sleep patterns, thus reducing the negative impact of emotional disorders on sleep quality. A multifaceted therapeutic approach that integrates these aspects could be particularly beneficial for improving the overall wellbeing of children with DS and ED. At the same time, it should be acknowledged that the assessment of sleep relied solely on parent-report through the SDSC. Although this instrument is well validated, parental perceptions may be influenced by the child’s emotional and behavioral difficulties. This potential reporter bias suggests that our findings, while consistent with previous literature, should be interpreted with some caution.

The results of the present study should be interpreted in light of some limitations. First, as a comparative study, no causal inferences can be drawn regarding the relationship between ED and clinical characteristics. The study design does not allow for the determination of cause-and-effect relationships, and future research using experimental or longitudinal designs is needed to explore potential causal relationships. Second, the assessment of sleep disturbances relied on parent reports; future studies should incorporate additional measures, such as actigraphy, to provide more objective information on sleep quality. Third, not all participants completed the Beery-VMI and TFL subtests, resulting in unequal subgroup sizes across key measures. This may have introduced sampling bias and limits the generalizability of our findings. Finally, the cross-sectional design of the study limits the understanding of the temporal dynamins between ED and other clinical features. A deeper understanding of the relationship between ED and psychopathological, neuropsychological, and sleep profiles in DS would benefit from longitudinal studies with large samples.

Despite such limitations, the present study provides significant insights into the complexities of ED in children and adolescents with DS. Our results indicate that children with DS and co-occurring ED not only exhibit more pronounced psychopathological symptoms and sleep disturbances but also face greater difficulties in visual-motor integration compared to their peers without ED. These findings highlight the importance of considering ED when assessing and planning interventions for children with DS, as it may have significant implications for their neuropsychological functioning, behavioral profile, and overall wellbeing. Future studies could build on the framework proposed by Cole et al. (2017) to examine whether children with DS and co-occurring ED exhibit distinct patterns corresponding to the four subtypes of dysregulated emotions—persistent, disruptive, contextually inappropriate, or rapidly shifting. Understanding these different forms could offer deeper insight into the heterogeneity of ED clinical manifestations in this population and guide more tailored clinical assessments and interventions. Moreover, future research should continue to explore these associations, particularly through longitudinal studies, to better understand the long-term effects of ED on children with DS and inform more targeted interventions.