Social Avoidance in Infancy Predicts Autism Severity in Boys with Fragile X Syndrome, Study Says

Boys with fragile X syndrome who show high levels of social avoidance in infancy are more likely later to have increased severity in autism spectrum disorder symptoms but reduced severity in attention-deficit/hyperactivity symptoms and anxiety, a study finds.

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

Autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD) and anxiety are three of the most common psychiatric disorders affecting children, with many patients often exhibiting social avoidance at an early age.

While most studies on social avoidance have focused on “typically developing” children, a few have examined social avoidance in genetic subgroups, such as fragile X, which are at an elevated risk for these psychiatric disorders. About 82%–98% of males with fragile X show socially avoidant behaviors.

In this study, researchers evaluated the association between social avoidance in infancy and the subsequent outcomes of ASD, ADHD, and anxiety in boys with fragile X. The study included 74 males with fragile X, who had undergone a total of 201 assessments. The age of the boys ranged from 4 to 62 months at their first assessment, and from 23 to 70 months at their final assessment. The average time between the first and final assessment was 29.39 months. Nine participants had one assessment, while the rest had at least two.

The researchers hypothesized that fragile X patients who exhibit higher ASD and anxiety symptoms would also exhibit higher levels of social avoidance that may intensify with age. They also hypothesized that this relationship would not be associated with ADHD symptoms because, while social avoidance is a core feature of ASD and anxiety, it tends to be more of a secondary characteristic in ADHD-related issues.

The researchers used the Social Avoidance Scale to record socially avoidant behaviors, which were divided into three domains: physical movement, facial expression, and eye contact during the first minute and the last hour of an interaction.

ASD, ADHD, and anxiety symptom outcomes were measured using parent-reported questionnaires.

Results showed that increased social avoidance across infancy and preschool was associated with elevated ASD symptom severity. On the other hand, social avoidance was associated with reduced ADHD and anxiety symptom severity in males with fragile X.

“Collectively, elevated 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 and anxiety severity at outcome,” the researchers wrote.

“Overall, these results suggest that elevated social avoidance emerging during infancy may be a salient marker for the onset for ASD and of reduced risk for ADHD and anxiety in males with FXS,” they said.