Background
The U.S. Department of Health and Human Services has linked physical activity to improved health and reduced risk for long-term disease in youth, adults, and older adults [
75]. Physical activity, generally, is associated with decreases in symptoms of depression and anxiety in adults [
5,
21,
34,
66], increases in neurocognitive performance in older adults [
48], and improved mental health and self-esteem in children and adolescents [
11,
16,
35,
42,
46,
49,
71,
76]. Moreover, physical activity related to participation in team sports may be particularly beneficial for mental health and depression [
17,
24,
35], suggesting that different aspects of activities might distinctly impact mental health. Although previous work has characterized differences in childhood depression related to team and individual sports [
35], no research, to date, specifically examines the relationship between other aspects of activities (e.g., physical or non-physical; social or non-social) and depressive symptoms in children.
The prevalence of internalizing disorders in youth underscores the importance of identifying protective factors that may inform prevention and intervention [
20,
51]. Nearly 20% of youth aged 13–18 already have experienced major depression [
3] and over 30% receive anxiety disorder diagnoses [
45]. Among young people who receive diagnoses, fewer than half receive treatment [
57], often after symptoms have become severe enough to warrant intervention. Furthermore, internalizing diagnoses are likely underreported [
72] and the prevalence of youth internalizing disorders may, therefore, be understated. Although efforts to develop early detection instruments will be key to providing precise care for youth, understanding the impact of various childhood experiences on protecting against internalizing symptoms is a critical step forward.
Late childhood and early adolescence is not only a time when a number of mental health problems begin to emerge [
45], but also a time when parents, educators, and policymakers scrutinize over which activities will lead to the healthiest outcomes for young people. Although participation in organized activities is believed to be important for boosting well-being and adjustment in youth [
25], research on the optimal number and type of activities for mental health yields mixed findings. Overall diversity, or breadth, of activities has been linked to positive adjustment in adolescents and young adults [
29]. However, specific outcomes vary by activity type, with research consistently showing that sport participation may have long-term mental health benefits [
11,
42,
70]. Among individuals with a history of adverse childhood experiences, team-sport participation in adolescence has been related to increased resilience against later internalizing disorders in adulthood [
24]. Physical activity also has been associated with improvement in depressive symptoms in adolescents aged 13–17 [
16]. While less is known about whether younger children receive the same benefit, recent work analyzing data from over 4000 children across the US (a subset of the data included in this study) reported that team sport participation was associated with lower levels of depressive symptoms, specifically in male children [
35,
36]. Taken together, previous work suggests that physical activities can help mitigate depressive symptoms in youth.
Like physical activity, social factors can be protective against depression and anxiety during childhood and adolescence [
38]. Youth who experience loneliness or peer rejection are at increased risk for depression in later adolescence and adulthood [
13,
63,
64]. Additionally, quality of friendships has been shown to predict youth behavior with positive relationships leading to favorable outcomes and negative relationships increasing risk for poor outcomes [
52].
Importantly, however, physical activity and social factors are not necessarily independent. Rather, many youth activities involve both physical and social components, and social connections such as close friendships, potentially forged and maintained in these contexts [
26], may explain some of the protective effects of physical activities on depressive symptoms. For example, Babiss and Gangwisch [
4] showed that participation in sports may lead to decreases in harmful behaviors and increases in perceived social support and self-esteem in adolescents. Similarly, the presence of prosocial peers has been found to mediate the relationship between time spent in sports and depression in high school students [
28]. In contrast, participation in social
non-
physical activities such as performing arts can increase feelings of social isolation over time [
8], indicating that the influence of social connections on mental health outcomes may not be equal across all activities [
14]. To date, no studies have systematically disentangled the relative benefits of social aspects of physical activity as they relate to depressive symptoms in youth. In other words, it remains unclear whether physical activity itself is protective, or whether the social aspect of some physical activities account for some or all of their benefits for children’s mental health. Accordingly, researchers have used different approaches to capture and categorize youth activities.
Prior work broadly examining youth activities suggests that person-centered approaches, which evaluate unique profiles of individuals’ overall activity participation but do not explicitly test social aspects, provide a more holistic account of how young people spend their time [
7,
27]. Different activities have distinct social and emotional demands [
12,
50], suggesting that person-centered approaches may be improved by explicitly examining the social aspects of youth activities while examining individuals’ unique profiles of activity participation. Though important, investigations of the social components of youth activities are sparsely represented in the literature, partially because prior research relies on measures that do not explicitly investigate social- and non-social factors [
30]. One reason for the paucity of research on social components of youth activities may be previous methodological constraints. However, recent advances in technology such as Amazon’s Mechanical Turk (MTurk) provide reliable and efficient online platforms for collecting psychological and other data [
60,
65]. MTurk offers a flexible, easy-to-implement method for “crowdsourcing” opinions [
15], such as those about the dynamics of social- and non-social youth activities.
Current studies
Here, we investigate the relationship between different types of youth activities and depressive symptoms. In the first study, we assess the degree to which different physical and non-physical youth activities are perceived as being social and team-oriented in an adult sample using MTurk. In the second study, we evaluate associations between caregiver-reports of youth activities assessed with the Sports Activities Involvement Questionnaire (SAIQ) and youth internalizing symptoms assessed with the Child Behavior Checklist (CBCL) using data from the first release (NIMH Data Archive (NDA) Release 1.1,
https://doi.org/10.15154/1412097) of Adolescent Brain Cognitive Development℠ Study (ABCD Study
®) data (
n = 4520 children ages 9 and 10). In particular, we focus on depressive symptoms, given previous research showing an association between physical activity and depressive symptomatology [
17,
24,
35]. Next, we assess the strength of any observed effects by testing them in the second data release (NDA Release 2.0,
https://doi.org/10.15154/1503209) of ABCD data (
n = 7355 children ages 9 and 10) for replication. Finally, we evaluate whether engagement in social–physical activities is related to increases in social connections (e.g., close friendships). In supplementary analyses, we test whether physical activity is related to depressive symptoms over and above other internalizing symptoms (e.g., somatic, anxious). Given previous work showing that team sports, specifically, are associated with the largest improvements in mental health, our overarching hypotheses are that: (1) participation in social–physical activities, but not other types of activities, will be associated with lower depressive symptoms; and (2) social connections, in general, will mediate the relationship between social–physical activities and lower depressive symptoms.
Study 1: data-driven categorization of youth activities
Although previous work has examined physical activity as a protective factor against depression [
16], the social aspects of youth activities have not been systematically evaluated. In Study 1, we examine how two samples of adults characterize youth activities reported on the ABCD Sports and Activities Involvement Questionnaire (SAIQ; described below), a parent-report measure. To evaluate the social- and team-dimensions of SAIQ activities, we collected Qualtrics survey data using Amazon’s MTurk.
Discussion
Physical activity is important for building healthy habits and protecting against mental and physical health problems. The primary goal of these studies was to use a data-driven classification method to investigate different aspects of youth activities that relate to depression in childhood, specifically focusing on social factors. We established that different types of youth activities can be reliably categorized on the degree to which they are physical and social/team-oriented. Building on previous work showing positive associations between team sports and mental health [
16,
23,
24,
35,
42], we show that social–physical activities may be one protective factor against depressive symptoms in children. Furthermore, close friendships partially mediated the relationship between participation in social–physical activities and depressive symptoms. This finding highlights a novel pathway that provides insight into how social–physical activity participation may specifically protect against depression in children.
Previous work has identified that the social aspect of physical activity is important for maintaining activity participation [
39]. Our results indicate that the social aspect of physical activities may present a unique opportunity for forging close friendships in childhood that ultimately increase perceived belongingness and other factors that protect against depression [
10,
62,
67]. In contrast, non-social–non–physical activities were found to be associated with higher depressive symptoms. Taken together, these findings suggest that participation in any type of youth activity may not provide the same benefits or protect against the same risks. It is possible that non-social–non-physical activities may increase feelings of isolation in childhood, while social–physical activities may boost opportunities for close friendship and peer-support. These results demonstrate that social–physical activities may provide additional benefits above and beyond those of other types of youth activities. Loss of social connections has been linked to depression during adolescence and emerging adulthood [
56]; therefore, getting children engaged in social–physical activity at an early age may be important for parents, educators, policymakers, and mental health professionals to consider. As depression is a form of psychopathology that can be resistant to both pharmacological and cognitive interventions [
22,
74], and in light of other work showing that interventions such as cognitive behavioral therapy can be reinforced by exercise programs [
55,
68], our results further highlight and specify one factor that may be important to target at an early age. Additionally, depression has been found to predict physical health status [
32,
43] and physical activity levels [
54], so encouraging youth to participate in social–physical activities may promote long-term positive outcomes and prove useful in bolstering healthy development across multiple domains.
The current findings build on previous work demonstrating that youth activities are one feature of children’s lives that are important for mental health outcomes, yet several limitations must be considered. First, while our analyses utilized a data-driven empirical method for categorizing youth activities, our study was constrained by the activities assessed on the SAIQ, which fails to include some popular youth activities (e.g., riding bikes). Second, parent/caregiver-report was used for estimating clinical symptoms and activity involvement. Although the CBCL is widely used with strong validity and reliability [
1], past work suggests that it may be difficult for parents to identify internalizing symptoms particularly in childhood [
72]. Future work may be enhanced by including youth-report measures of both internalizing symptoms and activity participation, in addition to utilizing more precise measures of physical activity such as FitBits or other pedometer technology. Third, our findings vary from recent work showing that team-sports are associated with lower depression in only males [
35]. This discrepancy may be driven by different approaches in the measurement of youth activities (e.g., varying definitions of sports versus physicality) and differences in exclusionary criteria. For example, 328 additional subjects were removed from Gorham et al.’s [
35] analyses due to missing or unusable brain data. Similarly, Gorham et al. [
35] used categories that are not mutually exclusive, whereas in our analyses activities were sorted into one of four categories. Overall, we believe our results complement Gorham et al. [
35] and both studies provide important information for future research about youth activities and mental health. Fourth, while non-parametrically significant, the overall magnitude of the association between social–physical activity and depression is small. This effect, however, replicated across independent samples, and significance was evaluated with permutation testing. Thus, while small, the relationship between social–physical activities and symptoms of depression appears robust, reliable, and replicable. Furthermore, we tested the effects of activity participation on depressive symptoms in parsimonious models that included all categories of activity at the same time, a conservative approach previously used by Fredricks and Eccles [
29]. Taken together, although our results suggest social–physical activity participation is associated with lower depression in children, additional research is needed to characterize the real-world effects of interventions based on social–physical-activity for depression in youth.
The observed mediation effect—that close friendships partially mediate the relationship between social–physical activity participation and depressive symptoms—fills a gap in the literature about team-sports and depressive symptoms in youth. However, these analyses are limited in their ability to determine directionality. Recent work suggests a unidirectional protective relationship between physical activity and major depression in adults [
76], but future work poised to assess directionality between activity participation and mental health throughout development is needed. For example, a core feature of several internalizing disorders is self-selecting out of various activities [
2], and it is reasonable to expect that anxious or depressed youth may choose not to participate in activities (e.g., due to lower levels of motivation or social phobia). Our specificity analysis, detailed in Additional file
1: Section 3, shows that social–physical activities do not mediate the association between social connections and depression. This result suggests a distinct pathway whereby participation in social–physical activities may lead to an increased number of close friends, which in turn affects depression. Although we used a crowd sourcing approach to collect ratings of the social- and team-dynamics of youth activities, it is also possible that not all youth have the same experiences of social dynamics within any one activity. Future work may be improved by including youth-report measures rather than parent-report measures of the social-dynamics they perceive during various activities. The current study design does not allow us to determine causality; however, forthcoming releases of ABCD longitudinal data will allow us to evaluate how associations between youth activities and mental health change throughout development.
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