Early adversity and family resilience factors in children with autism spectrum disorder: A narrative review

Abstract

Global estimates indicate that autism is a neurodevelopmental condition that is currently diagnosed in 1 in 100 people across the world. Autistic children can experience deficits in social communication, often linked to difficulties with joint attention and facial emotion recognition. Restrictive repetitive behaviors and interests (RRBIs) are also part of the diagnostic criteria of autism and are associated with lower adaptive skills. Due to social challenges and RRBIs exhibited by autistic children, they may be at higher risk for experiencing social and familial stressors. In non-autistic children, early adversity is predictive of deficits in executive functioning, neurological changes, and poor adult health. However, resilience factors have been identified, which can offset the negative impacts of adversity. In autistic children, these protective factors may have differential downstream influences on children's outcomes due to cognitive and social difficulties. In this narrative review, we report that autistic children are more likely to experience familial and environmental stressors compared to non-autistic children. Resilience factors such as positive parenting, sleep, social relationships, and executive functioning skills were identified as key areas for future research.

Lay summary

Children with autism are statistically more likely than their peers to be exposed to adverse childhood events including bullying, parental divorce, and poverty. The more severely affected a child is by autism the greater the likelihood they will be exposed to early life stress. This indicates that the most vulnerable children with autism who have limited adaptive skills to promote resilience to stress may have the highest exposure to stressful events during their childhood. In turn, a better understanding of how early adversity impacts children with autism is needed as well to characterize resilience factors that promote optimal outcomes. In this review of the literature, it was found that children with autism may experience more stress from their family and surroundings compared to children without autism. Factors that can help these children cope better were identified, including supportive parenting, getting enough sleep, having friends, and having good problem-solving skills. This research could help parents and teachers better understand how to support children with autism who are experiencing early adversity.

Introduction

Autism is a neurodevelopmental condition including traits of stereotypic behaviors, mental inflexibility, and differences in social communication (American Psychiatric Association, 2012). A recent meta-analysis estimated that globally autism is diagnosed in approximately 1 in 100 people (Zeidan et al., 2022). Autistic children and youth are at higher risk for experiencing both familial and social stressors, but little is known about the long-term impacts of these events on cognitive and health outcomes. Furthermore, social stressors experienced by the mother during the perinatal period may genetically predispose children for neurodevelopmental disorders such as autism (Leppert et al., 2019). While a growing body of research has explored resilience factors in non-autistic children, few studies have examined what factors can protect children on the autism spectrum against these events. The following narrative review explores the current literature on the physical and psychological impacts of early adversity, as well as the relevant resilience factors in both autistic and non-autistic children. While we are exploring the separate impacts of adverse events, it is important to recognize that these events have a greater cumulative impact, as demonstrated by Rutter's index of psychosocial adversity (Kanina et al., 2023). Understanding the literature behind these factors can help lower the potential vulnerability to adversity among children on the autism spectrum, and instead promote resilience.

Early adversity and neurological development

Prolonged periods of stress can have a broad range of impacts on development, particularly in childhood. Early adverse experiences can be defined as any events which impede a child's ability to build stable relationships or threaten their ability to feel safe and secure within their environment (Jones, Merrick, et al., 2020). Within the scope of this review, “early” adverse experiences can refer to any time before the age of 21, when neurological development is largely complete (Tierney & Nelson, 2009). Interest in the short- and long-term impacts of adversity has increased in recent years, with more studies examining the role of these events on physical, psychological, and cognitive outcomes. This field of study grew increasingly relevant with the COVID-19 pandemic, as the impacts of COVID-19 were particularly harmful to children with disabilities, neurodevelopmental disorders, and chronic health issues (Jones, Woolfenden, et al., 2020; Masi et al., 2021).

Negative experiences in childhood such as these impact neurological development, and are associated with alterations in the amygdala, hypothalamic-pituitary-adrenal (HPA) axis, and the prefrontal cortex (PFC) (Andersen, 2022; Fisher et al., 2016; Taylor & Rogers, 2005). The amygdala and the regions in the HPA axis are responsible for responding to stress and regulating emotion. Consequently, children who experience early life stress often have difficulties with emotional regulation, displaying externalizing problem behaviors later in life (De Bellis, 2005; De Bellis & Zisk, 2014; Hornfeck et al., 2019).

Other brain regions significantly impacted by early adverse experiences are the hippocampus and the PFC. The PFC is often considered the “control center” of the brain and manages executive functioning skills such as working memory, organization, planning, inhibition, and mental flexibility (Moriguchi & Hiraki, 2013; Peng Yuan & Raz, 2014). Studies comparing cognition in children with early life adversity found those who experienced higher levels of adversity had significant deficits in working memory, planning, and inhibition when compared to children from the control group (Carrera et al., 2019; Fay-Stammbach & Hawes, 2019; Glaser, 2000). The associated difficulties with executive functioning skills also impact the academic success of these children as they enter school age (Lafavor et al., 2018; McDermott et al., 2012). Understanding the independent impacts of adversity on brain development is particularly relevant when considering autistic children, as these children are already more likely to exhibit lower executive functioning skills (McClain et al., 2022).

Physical and mental health impacts

Childhood adversity is associated with a variety of physical and mental health challenges from adolescence into adulthood. In terms of adult physical health, an association has been observed between childhood adversity and increased inflammation, cardiovascular disease, and diabetes in adults (Basu et al., 2017; Chiang et al., 2015; Friedman et al., 2015). This is likely due to the increased activation of the autonomic nervous system, which is closely tied to the immune system (Chiang et al., 2015; Nusslock & Miller, 2015). Early adversity is also associated with longer disability leaves from the workplace in the United States, even when controlling for preexisting diabetes and cardiovascular disease (Laditka & Laditka, 2019).

Adverse childhood events have similar associations with poor mental health. Positive correlations have been observed between the number of adverse childhood events and the number of depressive symptoms in adolescents, suggesting these events were a potential risk factor for developing depression (Luby et al., 2017). Additionally, the association between childhood trauma and adult schizophrenia is well established (Figueiredo et al., 2021; Read et al., 2005).

Financial adversity

Aside from childhood trauma, financial adversity is well represented within the research, particularly in relation to the cognitive impacts it may have on children and youth. Studies have shown that lower socioeconomic status (SES) is predictive of lower executive functioning skills and language abilities in children and youth (Lawson et al., 2018; Merz et al., 2019; Wade et al., 2022). SES is also a predictor of cortical thickness (Brito et al., 2017). A similar study reported that residing in a low-SES household was associated with lower white matter volumes in the brain, as well as decreased cognitive flexibility (Ursache & Noble, 2016). These changes in cortical thickness may be one potential mechanism which contributes to the higher risk children from low-income families have for developing Attention Deficit Hyperactivity Disorder (ADHD) symptoms (Machlin et al., 2020).

Aside from individual changes in cognition, research has also been devoted to understanding the impact of financial adversity on a broader scale, especially when looking at larger trends in neighborhoods. One study conducted in the United States examined the cognitive abilities of children compared to the deprivation level of the neighborhood in which they lived. Neighborhood deprivation was measured using a self-report measure and national survey data and was comprised of factors such as the average level of education of parents, average unemployment rate, number of single-parent families, and number of families living below the poverty threshold. The results from their study showed that regardless of individual SES of participants, neighborhood deprivation was a significant predictor of executive functioning skills, in addition to predicting surface area on the PFC region of the brain (Vargas et al., 2020).

When examining the association between financial adversity and the prevalence of autism diagnoses, the findings are somewhat mixed. While one national US study showed a positive correlation between financial adversity and the rate of a diagnosis of autism in children, several others have shown an association between higher SES levels and diagnoses of autism (Durkin, Baio, et al., 2017; Durkin, Meaney, et al., 2010; Thomas et al., 2012; Wong & Yu, 2023). However, some researchers have posited that the increased prevalence of autism in higher-income households may be due to better access to services, along with earlier intervention for children in higher SES neighborhoods in the United States and Canada (Durkin et al., 2017; Siddiqua et al., 2020; Thomas et al., 2012). Although there is a large field of literature concerning the association between SES and cognitive development in neurotypical children, fewer studies have investigated whether similar patterns exist among people on the autism spectrum. A study examining the cognitive abilities of autistic children found that financial adversity was a significant predictor of global intelligence in school-aged autistic children, even when controlling for SES (Kuenzel et al., 2021). This finding supports previous evidence that financial instability may be particularly harmful for autistic children, especially when experienced in early childhood (Kerns et al., 2017).

Familial adversity

Outside of financial difficulties, familial adversity is a prominent type of adversity examined within this field. Familial adversity can include more common negative childhood events such as parental stress, divorce, or intermarital conflict. Unlike financial adversity, psychological changes are primarily associated with increased familial stress during childhood. For example, one study examined the association between familial adversity, stress reactivity, and externalizing behaviors in preschool children; their results showed that a higher number of familial adverse events was positively correlated with both higher stress reactivity and increased externalizing behaviors (Obradović et al., 2010). Another study found that among those who were genetically at risk for developing depression, higher familial stress during childhood was significantly associated with depressive symptoms. At the same time, participants who carried the gene but reported low family stress showed low depressive symptomatology (Taylor et al., 2006). These findings suggest that familial adversity may play a significant role in the way genes are expressed and the subsequent psychological outcomes.

Family adversity is also associated with poorer outcomes for children's externalizing behaviors. Family adversity (such as harsh parenting practices and parental stress) and HPA axis functioning were both found to be predictive of externalizing antisocial behavior in kindergarten-aged children (Goulter et al., 2021). These patterns seem to persist over time: a longitudinal study conducted in the United Kingdom followed a large cohort of children from infancy to adolescence, and compared factors in their home environment to the children's mental health and risk-taking behaviors over time. They found that children who were classified in the high-familial adversity group (including either two-parent/high intermarital conflict or single-parent households) before the age of 3 years old were at higher risk for committing criminal behavior and reported increased mental health issues in adolescence (Wadman et al., 2020). The authors suggest that there may be a critical period (before school age) when children are most susceptible to the negative impacts of familial stressors.

Caregiver strain

Autistic children are more likely to experience adversity within their family unit: a large body of studies conducted over the last 30 years have shown that parents of autistic children experience higher levels of stress than parents of non-autistic children (Benson & Karlof, 2008; Bouma & Schweitzer, 1990; Schieve et al., 2006; Van Steijn et al., 2014). Hallmark features of autism also play a role, as these are significant predictors of stress levels in parents of autistic children (Pastor-Cerezuela et al., 2016). For parents of autistic children, stress proliferation often occurs, whereby the presence of one type of stressor (i.e., features of autism) leads to an increase of another type of stressor (i.e., parent anger) in a cyclical nature (Benson & Karlof, 2008). This cycle seems to negatively impact parent mental health; both features of autism and stress proliferation were predictors of depressive symptoms of parents of autistic children (Benson, 2006). A recent study examined which types of adversity were the greatest risk factors for autistic children, finding that autistic children were at higher risk for experiencing familial adversity than their non-autistic peers (Kuenzel et al., 2021). However, little research to date has focused on the impacts that parental stress has on their children directly.

Social stressors

While there is a broad base of literature focused on the short- and long-term impacts of adverse early life experiences on non-autistic children, less is known surrounding the impacts of these events on autistic children and youth. Within the context of this review, social adversity can encompass any situations which bring on significant levels of stress for children regarding peer relationships (i.e., bullying, conflict with peers, social isolation). Children on the autism spectrum are more likely to experience adversity in social settings and are more likely to be targets of bullying (Sterzing et al., 2012; Tipton-Fisler et al., 2018; van Schalkwyk et al., 2018). These trends seem to continue up into young adulthood, with college-aged autistic youth reporting higher incidence of bullying than youth with intellectual disabilities, or their neurotypical peers (Tipton-Fisler et al., 2018). Difficulties with peer victimization may be related to typical features of autism, with social-communication challenges being common for people on the autism spectrum (Matthias et al., 2021). Autistic children also experience higher levels of stress during play and social situations than non-autistic children, even without experiencing any peer victimization (Schupp et al., 2013). Consequently, autistic children are also more likely to experience school refusal in due to bullying compared to their non-autistic peers (Ochi et al., 2020).

Social difficulties and challenges with communication are one of the earliest ways that parents and clinicians can identify that a child may be autistic (Gangi et al., 2021; Yirmiya & Charman, 2010). One contributor to these difficulties may be language development; autistic children often experience delayed or altered language acquisition when compared to their neurotypical peers (Davidson & Ellis Weismer, 2017). Several studies collecting longitudinal fMRI data from autistic children have observed that children within this group have atypical functional connectivity in the language centers of the brain, particularly between the auditory cortices (Hernandez et al., 2015; Liu et al., 2020).

At the same time, autistic children show difficulties with joint attention, which may contribute to delays in language development and communication skills. Joint attention is the ability to spontaneously attend to stimuli at the same time as another person within a social context and is instrumental in early development and learning (Harrop et al., 2014). In toddlers, joint attention is a predictor for the development of language abilities in later in life, including verbal expression and comprehension skills (Adamson et al., 2019; Morales et al., 2000). Deficits in joint attention have been shown to be a reliable early predictor of a diagnosis of autism within the first year of life (Chawarska et al., 2013; Poon et al., 2011). Aside from language development, joint attention may also be a predictor of social competence for children on the autism spectrum later in development: a longitudinal study by Freeman and colleagues found that among children on the autism spectrum, those with higher levels of joint attention at age three were reported to have closer friendships and less conflict with peers than those with lower levels of joint attention in toddlerhood (Freeman et al., 2015).

Another contributor to the social differences experienced by children and adolescents on the autism spectrum are challenges with matching emotions to their corresponding facial expressions of others (Oerlemans et al., 2014; Wieckowski & White, 2017; Wingenbach et al., 2017). This difficulty may impede the child's ability to successfully participate in social conversations with family members or peers. When considering the specific emotions most difficult for children and youth on the autism spectrum to identify, studies have shown that expressions associated with ambiguous or negative emotions such as surprise, fear or disgust are most often misidentified (Kuusikko et al., 2009; Yeung et al., 2019). Additionally, facial emotional regulation seems to be increasingly difficult when the emotion is being displayed at a lower intensity (Wingenbach et al., 2017), or when the complexity of the emotion increases (i.e., “sadness” vs. “embarrassment”) (Cassidy et al., 2015). These findings suggest that autistic children and youth may struggle with many of the intricacies of social interactions which non-autistic children can comprehend automatically.

Functional and adaptive behavior

Restrictive repetitive behaviors and interests (RRBIs) are a common feature of autistic people. RRBIs include a broad range of behaviors, from stereotypic motor movements (i.e., rocking back and forth, leg tapping) to vocal scripting (repeating phrases, words, or sounds outside of the correct context) to showing extremely narrow interests (extreme adherence to routines, fixation on a particular topic or subject area) (Hong & Matson, 2021; MacDonald et al., 2007; Wunderlich & Vollmer, 2015). More recent literature on these patterns has categorized them into two types of behavior: higher-order RRBIs and lower-order RRBIs. Higher-order RRBIs are usually classified as rigidity in abstract thinking or mental inflexibility, such as needed to follow routines very strictly or showing narrow interests. By contrast, lower-order RRBIs are usually motor-related and increase sensory input, such as rocking back and forth (Lin & Koegel, 2018; Zetler et al., 2022).

Longitudinal data have suggested that repetitive behaviors are observed in children who are later diagnosed with autism, as early as 12 months old (Wolff et al., 2014). Increased frequency of RRBIs is associated with lower adaptive functioning (or practical daily living skills), more difficult social relationships, and poorer eating habits (Hong & Matson, 2021; MacDonald et al., 2007; Shiloh, 2021). Despite these negative associations with RRBIs, it is important to view these behaviors through a functional lens and consider why they are maintained. Early research in stereotypic and self-injurious behavior hypothesized that these behaviors often lead to positive or negative social reinforcement. For many autistic children, engaging in RRBIs may lead to gaining increased attention from a preferred person, or a means of escape for a non-preferred (Repp et al., 1988; Rispoli et al., 2018). Another study has hypothesized that both high- and low-order RRBIs are maintained because they alter sensory stimulation, as many autistic individuals experience difficulties with sensory modulation and can feel under- or over-stimulated in their daily environment (Moseley et al., 2019; Zetler et al., 2022). Similarly, there have been mixed associations between the social features of autism and adaptive skills, with some studies finding as positive correlation between the two, and others finding a negative correlation between them (Berends et al., 2023; Bradshaw et al., 2019). It is vital for parents and caregivers to understand the function of these behaviors, and how these behaviors are mechanisms by which people on the autism spectrum can adapt to the world around them.

Lifestyle factors promoting resilience

While early adversity has clear negative impacts on the psychological, neurological, and physical health of autistic and non-autistic children, certain factors can improve outcomes for children experiencing adversity. For decades, research has been dedicated to understanding which factors promote resilience and positive outcomes among those experiencing adversity. Within this research, resilience can broadly be defined as both an outcome and a dynamic process, whereby the ability to positively adapt to adversity allows one to both avoid the negative impacts of adversity and develop strengths (Masten, 2011; Panter-Brick & Leckman, 2013). When considering positive longitudinal outcomes, it is vital to understand the context within which a child develops, including the interaction between biological, psychological, social, and ecological factors (Bronfenbrenner & Morris, 2006). As Ungar and coauthors found in their review of ecological factors of resilience in children, a child's lifestyle and environment are significant predictors of resilience. In fact, the authors found that as children experience more adverse events, ecological factors such as instructional strategies used in the child's classroom are increasingly important (Ungar et al., 2013).

Sleep is one such lifestyle factor which has been associated with resilience in both clinical and non-clinical populations. In a recent study of newly employed Chinese nurses, better sleep quality was positively correlated with increased resilience, and negatively correlated with perceived stress (Lin et al., 2023). A meta-analysis of studies examining the relationship between sleep quality, sleep duration, and resilience found across nearly 2,000 studies, that there was a positive correlation between sleep quality and resilience in healthy samples (Arora et al., 2022). While this correlation does not imply any direct relationship between better sleep quality and increased resilience, it does indicate that sleep may play a role in promoting positive outcomes for those undergoing adversity. Maintaining proper sleep is particularly important for autistic children, as recent data suggest that autistic children are three times more likely to be diagnosed with a sleep disorder, compared to non-autistic children (Cortese et al., 2020). Because sleep disturbances can exacerbate preexisting challenges with communication and attention in autistic children (Berenguer et al., 2024; Cortese et al., 2020), promoting healthy sleep in these children is particularly vital.

Social relationships are particularly important in promoting resilience for those undergoing prolonged stress; community support and positive relationships with caregivers have been identified as protective factors for child adversity (McGee et al., 2020). A meta-analysis of resilience factors in Western studies found that parental and social support were protective factors for children, significantly moderating the development of psychopathology later in life (Fritz et al., 2018). Other significant resilience factors include optimism, emotional regulation, and compassion, along with community support (Hamby et al., 2018). In a meta-analysis of studies exploring resilience factors for children and youth in residential care settings, Lou and colleagues found that across 15 studies, positive interpersonal relationships were associated with higher resilience, despite the increased vulnerability of children within this setting (Lou et al., 2018). Exploring how to protect children from the negative impacts of adversity will be crucial to promoting positive outcomes for children who are particularly vulnerable.

Examining risk and resilience factors related to cognitive outcomes is especially vital, as areas of cognition such as executive functioning are associated with better developmental outcomes. Executive functioning ability plays a significant role in the development of academic skills; studies have shown that executive functioning is a predictor of better mathematical problem-solving and number sense, spelling, handwriting, and reading abilities in school-aged children, when controlling for other cognitive abilities (Cheung & Chan, 2022; Fuhs et al., 2016; Khng & Ng, 2021; Valcan et al., 2020). A longitudinal study following a large cohort of students from kindergarten to grade six found that executive functioning skills were associated with better achievement in language and mathematics, even up to the sixth grade (Fuhs et al., 2014). Cognitive abilities are also associated with resilience in adults who experienced childhood abuse (DuMont et al., 2007). In neurotypical adolescents who have experienced adversity, non-verbal cognitive ability moderated the relationship between emotional arousal and problem behaviors (Flouri & Panourgia, 2011; McGee et al., 2020). Executive functioning skills such as working memory and cognitive flexibility have been identified as moderating the relationship between early life stress and increased socioemotional difficulties in neurotypical school-aged children (de Maat et al., 2022; Zhou et al., 2022). These skills have been positively correlated with resilience in both children and adults (Taylor & Ruiz, 2019; Wu et al., 2021). Therefore, exploring factors which predict higher cognitive performance and executive functions will give insight into what also promotes resilience.

The protective role of parenting

Within the resilience literature, parenting is well supported as a protective factor. In neurotypical children, the nurturing presence of a parent or caregiver allows their child to coregulate their emotions and decrease their stress response during stressful events. This phenomenon not only strengthens the attachment between parent and child, but also allows for proper neurological development of the stress-response regions of the brain, including those in the HPA axis and the amygdala (van der Kolk, 2003). The results of these brain changes can be seen when exploring the role of parenting in moderating the impacts of adversity on executive functioning. Among preterm-born children, having a nurturing relationship with a parent moderated executive functioning deficits in early childhood (Hirschberger et al., 2018; Taylor & Clark, 2016; Zvara et al., 2019). Secure maternal attachment also moderates salivary inflammation in infants (Measelle & Ablow, 2018). For children born with physical disabilities, a nurturing parenting style was associated with the child's ability to adapt to stress and process it effectively based on cortisol levels (Bugental, 2004). It should be noted that while these findings support the protective nature of maternal attachment, they do not in any way indicate that a mother's perceived “coldness” is responsible for any developmental difficulties their child experiences. These findings suggest that having a stable, secure relationship with a caregiver can protect children the from the biological impacts of adversity.

Similar trends have been observed when examining behavioral outcomes of children experiencing adversity. In children with intellectual disabilities, a close parental relationship predicted less externalizing problem behaviors in children over time, in spite of adverse events throughout development (Totsika et al., 2014, 2019). For children and youth experiencing homelessness, positive parenting acted as a moderator between adversity and both internalizing and externalizing behaviors (Labella et al., 2019). However, recent studies have shown that race plays a role within these relationships: children from minority groups report experiencing higher levels of adversity, while also receiving less access to protective factors like community support (Cho et al., 2021; Liu et al., 2020).

Few studies have examined the role of positive parenting as a protective factor for autistic children, especially in relation to the effects of adversity. However, emerging evidence suggests that positive parenting may function as a protective mechanism, similar to non-autistic children. Maternal warmth can offset behavioral problems and psychopathology associated with poverty in autistic children (Midouhas et al., 2013). A recent study examined the roles of both adversity and parenting on cognitive outcomes in autistic children when compared to a control group. The results showed that although autistic children were at higher risk for experiencing negative life events, positive parenting practices were associated with decreased familial stressors for children in both the autistic and non-autistic groups (Kuenzel et al., 2021). Conversely, both maternal stress and parent–child conflicts have been associated with increased conduct problems in autistic children (Flouri et al., 2015).

Conclusions

Autistic children face significant familial and social adversity early in life, which may be a risk factor for psychological, behavioral, and cognitive difficulties. For instance, autistic children may be more likely to experience familial adversity than non-autistic children due to high levels of parent stress. Parents of autistic children experience significantly higher levels of parental stress than those of non-autistic children (Benson & Karlof, 2008; Bouma & Schweitzer, 1990; Schieve et al., 2006; Van Steijn et al., 2014). Additionally, evidence suggests that parental stress is positively associated with increased autistic traits (Pastor-Cerezuela et al., 2016). Autistic children are more likely to be victims of social adversity due to bullying during school years, and as a result experience much higher rates of anxiety and depression than non-autistic peers (Statistics Canada, 2019; Sterzing et al., 2012; Tipton-Fisler et al., 2018; van Schalkwyk et al., 2018). Despite these associations, little research has considered the role of adversity on mental health outcomes in autistic children, or the protective role of parenting. Positive parenting can reduce overall family stress and may promote resilience in autistic children. Further research is needed to better understand the downstream effects of parenting on children's outcomes. However, as parenting style is a modifiable risk factor, interventions focused on positive parenting styles for autistic children may be future avenues of research. Everyday positive parenting practices in the home are most likely to have long-lasting effects on children's brain development along with their psychological, cognitive, and behavioral outcomes.

Limitations

As the literature on adversity and resilience in autistic children is an emerging area of research, many of the articles presented in this narrative review explore these factors in non-autistic children. The aim of this review was to explore the physical and psychological outcomes related to adversity and resilience in both neurodivergent and neurotypical populations, in order to highlight areas of research which should be further explored in autistic children.