A test of the Environmental Stress Hypothesis in children with and without Developmental Coordination Disorder

Highlights

• School-aged children with pDCD have higher levels of internalizing problems.

• Internalizing problems in children with pDCD are mediated by physical activity, BMI, and global self-worth.

• The underlying mechanisms of internalizing problems are different between boys and girls.

Abstract

Objectives

This study examined several underlying mechanisms hypothesized by the Environmental Stress Hypothesis (ESH) to explain the association between probable Developmental Coordination Disorder (pDCD) and internalizing problems.

Design/Method

A cross-sectional analysis involving 1206 children aged 12–14 years (79 pDCD, 6.6% of the sample) was conducted. Children received assessments of motor coordination, physical activity, BMI, global self-worth, and internalizing problems. Path analysis was conducted to examine overall model fit and sex differences.

Results

The results showed significant sex differences in the underlying pathways connecting pDCD to internalizing problems, indicating more mediating pathways through physical activity, BMI and global self-worth in girls, compared to boys.

Conclusions

Overall, we were able to find support for some of the pathways identified in the ESH in school-aged children. Results also suggest that the development of interventions may need to be sex specific.

Introduction

Mental health problems, including emotional and behavioural problems, are common in childhood with population-based estimates suggesting that more than 800,000 (approximately 14%) 4- to 17-year-old Canadian children have a mental disorder, with anxiety being the most prevalent childhood disorder at 6.4% (Waddell, McEwan, Shepherd, Offord, & Hua, 2005). Unfortunately, its prevalence may be increasing as a recent longitudinal study found that overall mental health-related medical use (e.g., emergency department visit, hospitalization, and outpatient care) has risen significantly between 2006 and 2011 (Gandhi et al., 2016). In order to prevent the early onset of mental health problems, it is essential to understand both the risk and protective factors that affect the development of salient mental health issues.

Individuals with Developmental Coordination Disorder (DCD) are a specific population considered to be at greater risk of developing mental health problems (Cairney, Veldhuizen, & Szatmari, 2010). For example, children with DCD have been found to be more likely to hold negative self-perceptions, have poorer emotional health, higher rates of inattention, poorer cognitive function, and experience greater social rejection and peer victimization, relative to typically developing children (Missiuna et al., 2014, Zwicker et al., 2013). This is particularly concerning as DCD is one of the most common childhood neurodevelopmental disorders (Cairney, 2015, Henderson and Henderson, 2002, Henderson and Henderson, 2003), affecting about 5% of all school-aged children (APA, 2013). A diagnosis of DCD is made if the motor impairments experienced are not better explained by intellectual disability and visual impairment, and/or attributable to other neurological conditions that would affect motor ability (e.g., muscular dystrophy or cerebral palsy). Importantly, people with DCD experience difficulties in executing motor tasks associated with daily living, which may include tying shoelaces, riding a bike, or handwriting (APA., 2000, APA., 2013). The onset of these problems occurs early in child development. As motor coordination is essential for engagement in physical activity across the life span (Payne and Isaacs, 2002, Stodden et al., 2008), motor impairments during childhood and through emerging adulthood may subsequently impact engagement in physical activities, leading to a variety of secondary consequences, such as obesity or poor cardiovascular function (Cairney & Veldhuizen, 2013). The consequences of DCD arising from inactivity may also have a negative influence on mental health. Due to a lack of participation in physical activity, children with DCD may not have opportunities to interact with their peers, develop social skills or positive self-perceptions, and build close relationships with friends (Piek et al., 2000, Poulsen et al., 2006, Wilson et al., 2013), all of which may further cause deleterious effects on their mental health. Indeed, school-aged children with DCD have been shown to be at greater risk for emotional and behavioural problems, such as depression, anxiety, and aggression (Losse et al., 1991, Missiuna et al., 2014, Piek et al., 2007, Pratt and Hill, 2011, Skinner and Piek, 2001). These emotional or behavioural problems have been shown to persist over time and into the adolescent period (Losse et al., 1991, Piek et al., 2010).

The Environmental Stress Hypothesis (ESH) is a framework developed to examine the effects of primary and secondary stressors associated with DCD on mental health, particularly internalizing problems in children and youth (Cairney, Rigoli, & Piek, 2013). It is based on Pearlin's Stress Process model (Pearlin, 1989, Pearlin et al., 1981), which specifies both direct and indirect effects of stressors, including life events, chronic strains, or trauma (Turner, Wheaton, & Lloyd, 1995), on psychological distress through both the mediating and moderating influences of perceived social support and psychosocial resources, such as self-esteem and mastery (Pearlin et al., 1981, Turner et al., 1995). Cairney et al. (2013) extended Pearlin's model by incorporating DCD, and other risk factors known to be associated with both psychological distress and motor coordination problem (e.g., physical inactivity and overweight/obesity) into a conceptual model (see Fig. 1). Specifically, the ESH posits DCD to be a primary stressor, which in turn initiates a cascade of secondary stressors, increasing the risk of internalizing problems (Cairney et al., 2013, Cairney et al., 2010c). Both social (i.e., perceived social support) and personal resources (i.e., positive self-concept) are hypothesized to play both mediating and moderating (or buffering) roles, acting to offset the potentially harmful secondary effects of DCD on internalizing problems (Cairney et al., 2013).

One of the more novel aspects of the ESH concerns the inclusion of physical inactivity (i.e., lower levels of participation in physical activity including organized sport and physical activity and active free play, or more time spent in sedentary behaviours such as increased use of screen time) and obesity as potential mediating factors connecting DCD to internalizing problems in children. The plausibility of these pathways is supported by research in both typically developing children and those with DCD/motor coordination problems. For example, research has shown that both physical inactivity and obesity are related to higher levels of internalizing problems in children and adolescents (Biddle and Asare, 2011, Hoare et al., 2014). Because children with DCD are more likely to be physically inactive and more than twice as likely to be overweight/obesity when compared to typically developing children (Cairney et al., 2005a, Cairney et al., 2010a, Poulsen et al., 2008, Zhu et al., 2011), an important pathway connecting DCD to internalizing problems is likely through physical inactivity and obesity (Cairney et al., 2013). One reason for this is the impact of both physical activity and obesity on perceptions of self: children who are physically active are more likely to report higher levels of self-worth and self-esteem when compared to less active children and youth (Reddon, Meyre, & Cairney, 2017). Children who are overweight and obese report lower levels of self-worth and self-esteem when compared to healthy weight children (Cairney et al., 2013). Other pathways are also possible. For example, Cairney et al. (2013) postulate that children and youth with DCD who are overweight/obese may experience higher levels of interpersonal stress (e.g., being bullied, teased and ridiculed in regard to both their body type and their coordination problems), that may negatively impact their sense of self-worth, leading to increases risk of depression and anxiety. Such pathways have not yet been tested in the extant literature. Understanding the mediating and moderating pathways that link DCD to internalizing problems may help to identify intervention targets for children with DCD to prevent and/or improve mental health.

There are additional pathways suggested by research that are not currently included in the EHS, but warrant investigation. For instance, previous systematic reviews have identified that lower physical activity and BMI may directly impact mental health (Biddle and Asare, 2011, Hoare et al., 2014) whereas the EHS specifies only an indirect relationship. In other words, there might be other potential mediating pathways from DCD to internalizing problems through physical activity or BMI.

Additionally, the EHS does not include sex specific pathways, yet existing evidence has shown that internalizing problems are more common in adolescent girls (Cairney, 1998, Petersen et al., 1993, Wade et al., 2002), and that girls are more likely to be physically inactive, have higher BMI, and have lower self-worth than boys in adolescence (Payne & Isaacs, 2002). Sex may also be an important risk factor for DCD, with some studies suggesting the prevalence is higher in boys (Missiuna, 1994), while other research has shown roughly equal numbers of boys and girls affected (Cairney et al., 2012, Missiuna et al., 2014). Given the importance of sex to both internalizing problems and the potential for sex differences in the prevalence of DCD, it may be the case that specific pathways in the model differ for boys and girls.

Despite an emerging literature examining selected pathways of the ESH to the study of mental health problems in children and youth with motor coordination difficulties, very few studies have systematically examined multiple underlying pathways identified in the model. The purpose of this study was to test several pathways of the ESH. In particular, we focus on the mediating effects of physical activity, body composition (i.e., BMI), and global self-worth as key pathways linking DCD to internalizing problems. Global self-worth represents one of the components of personal resources in the ESH (Cairney et al., 2013). Furthermore, global self-worth has been shown to be a stable predictor for internalizing problems and a strong mediator of the relationship between DCD and mental health difficulties (Lingam et al., 2012, Sowislo and Orth, 2013). We will also test additional pathways that are not included in the EHS, but have empirical support (pathways (c1) and (c2) in Fig. 2) and whether the same pathways are consistent for males and females or are sex specific. Based on the ESH, it is hypothesized that the relationship between DCD and internalizing problems would be sequentially mediated by physical activity, BMI, and global self-worth. Specifically, DCD will negatively impact physical activity and BMI, which in turn will negatively impact perceptions of global self-worth, which in turn will increase symptoms of anxiety and depression. We also hypothesize there will be a direct, residual effect of DCD on internalizing problems after mediation is taken into account. Finally, this study also hypothesizes that the pathways in the model will differ by sex.