Early Social Avoidance Can Predict Autism but Not Anxiety in Boys with FXS, Study Says

Increased social avoidance during infancy and early childhood in boys with fragile X syndrome (FXS) is associated with higher risk of autism spectrum disorder (ASD) and lower risk of attention deficit/hyperactivity disorder (ADHD) and anxiety, according to a recent study.

The study, “Infant Social Avoidance Predicts Autism but not Anxiety in Fragile X Syndrome,” was published in Frontiers in Psychiatry.

Fragile X is the most frequent single-gene cause of ASD and the most common cause of inherited intellectual disability. ADHD and anxiety are also common among children with fragile X.

Diagnosing ASD, ADHD and anxiety in young children can be a challenging task, “given the subtlety of behavioral features in early development coupled with the presence of features that represent typical variation or overlap across multiple disorders,” researchers said.

Therefore, identifying early predictors for these disorders can help both in prevention and intervention.

Social avoidance (avoiding interactions with others) has been associated with ASD, ADHD, and anxiety that often presents in early development. Studies evaluating the appearance of social avoidance and its relationship to future psychological disorders have been essential to provide efficient treatment guidelines.

However, so far, it is not clear whether social avoidance could serve as a predictor of psychological disorders in high-risk genetic subgroups such as children with fragile X.

Researchers studied the association between social avoidance and the development of ASD, ADHD, and anxiety in infants and children diagnosed with fragile X. They evaluated 78 boys under 6 who had been genetically diagnosed with fragile X and participated in two studies that resulted in 201 assessments.

Participants were recruited from past studies, national parent listservs, social media, the National Fragile X Foundation and the Research Participant Registry Core of the Carolina Institute for Developmental Disabilities at the University of North Carolina at Chapel Hill.

Social avoidance was evaluated using the Social Avoidance Scale (SAS), an index that comprises three domains — physical movement, facial expression, and eye contact. Higher ratings represent more socially avoidant behaviors. SAS comprises three sub-scales, and two ratings are assigned for each. The first rating is based on the first minute of social interaction and the second rating is based on the last hour of structured social interaction.

ASD symptoms were evaluated using the Childhood Autism Rating Scale (CARS), and the Child Behavior Checklist was used to assess ADHD and anxiety.

Increased physical avoidance, increased facial expressions of avoidance, and reduced eye contact were all predictors of ASD, ADHD or anxiety outcomes. “However, the relationships were dependent on the timing of the interaction (i.e., first minute or last hour) and parameter (i.e., average level or trajectory) with increased social avoidance predicting elevated ASD severity and, surprisingly, it also predicted reduced ADHD,” researchers stated.

Increased physical avoidance in the last hour, but not the first minute, as well as increasing facial expressions of social wariness during the first minute of interaction significantly predicted more severe ASD outcomes.  Reduced eye contact during the first minute of interaction also predicted more severe ASD symptoms in this population.

“Elevated social avoidance during social encounters with familiar people reflected the strongest indicator of more severe ASD symptomatology,” the researchers said.

On the contrary, increased social avoidance during initial interactions with unfamiliar people at the beginning of the assessment (first minute) was associated with reduced severity of ADHD and anxiety outcomes.

“Based on our results, increased social avoidance across infancy and preschool predicted elevated severity of ASD symptoms but reduced ADHD and anxiety symptoms in males with FXS,” researchers said.

The team hypothesizes that these results may reflect the fact that children who have less severe ADHD and anxiety symptom outcomes “may have learned to manage their emotions by physically retreating from the source of stress, in this case, the approach of an unfamiliar person.”

Further studies including factors such as girls with fragile X, longer observation times, and the inclusion of a control group will enable researchers to better understand the significance of these findings and create strategies to provide early treatment for children with fragile X who are at risk of developing psychological disorders.