Autism and social anxiety frequently occur together, but it has been difficult to tell whether this combination simply reflects more severe autistic traits or represents a distinct condition. Recent research published in Translational Psychiatry indicates that autistic adults with social anxiety tend to show more compliant social behaviors and possess larger amygdalas compared to those without social anxiety. The findings suggest that social anxiety in autism may constitute a unique behavioral and biological profile rather than just an overlap of symptoms.
Autistic individuals often experience social anxiety, with some estimates suggesting up to half of autistic adults face these challenges. This rate is far higher than what is seen in the general population. In everyday life, autistic people might avoid social situations because they struggle to interpret social cues or tolerate unpredictability, which can look very similar to standard social anxiety.
Because the two conditions can look so similar on the surface, “social anxiety can be missed or mischaracterized,” explained lead author Yu (Hannah) Hao, a professor of psychology at Ningbo University who conducted the research alongside Daniela Schiller at the Icahn School of Medicine at Mount Sinai. “Existing treatments may also be less effective when they do not address autism-specific experiences, such as difficulty interpreting social situations and coping with unpredictability.”
A major focus of recent science has been mapping how the brain processes these complex social interactions. For example, a 2025 study of autistic adults mapped out how participants navigate social scenarios, establishing a way to measure behaviors related to social closeness and interpersonal power.
At the center of the brain’s social behavior network sits the amygdala, a small almond-shaped structure that helps people process emotions and detect threats. Prior work covered by PsyPost in 2023 indicated that autistic individuals tend to have an unusually sensitive threat-processing system involving the amygdala when looking at faces.
Tracking this brain region over time has provided more clues about its role in social development. A 2021 study of adolescents tracked amygdala development and noted that changes in the size of specific amygdala regions are linked to the core social and communication challenges seen in autism.
These findings laid the groundwork for testing how brain structure and social behavior interact. Hao and the research team wanted to find out if autistic adults with social anxiety display a distinct set of social behaviors and brain features. By answering this question, they hoped to provide evidence that social anxiety in autism is a specific subtype that requires tailored diagnostic tools and treatments.
The research involved two complementary studies to examine both behavior and brain structure. The first study took place online and focused on behavioral differences. The research team recruited 575 young adults diagnosed with autism and a comparison group of 357 non-autistic adults. Within the autistic group, 145 participants reported having a professional diagnosis of social anxiety disorder.
Participants completed a naturalistic role-playing game designed to simulate everyday social decisions. As players navigated a storyline about joining a new school or exploring a new town, they interacted with virtual characters. The researchers measured two main dimensions of social behavior: affiliation, which involves seeking social closeness, and power, which involves taking control or asserting dominance in an interaction.
The results of this first study pointed to a specific behavioral pattern. Autistic adults with social anxiety were less likely to assert power in social situations compared to autistic adults without social anxiety. Instead, they tended to be more acquiescent, meaning they were more prone to yield control and comply with the requests of others.
“Acquiescent behavior should not be interpreted as an inherent weakness in autistic people; it may be an adaptive response to confusing interactions, previous negative experiences, or a desire to avoid conflict,” Hao told PsyPost. “The goal should not simply be to make autistic individuals more dominant, but to help them recognize manipulation, establish boundaries, and feel safer and more in control.”
This compliant pattern was unique to the autistic participants. Non-autistic individuals with social anxiety did not show the same tendency to surrender social power. The researchers also checked whether other common mental health conditions, like depression or generalized anxiety disorder, could explain the results. The tendency to yield power was linked exclusively to social anxiety, pointing to a distinct behavioral profile.
In the second study, the researchers brought participants into the laboratory to look for biological markers that might match these behavioral differences. This phase included 72 autistic adults and 72 non-autistic adults who underwent magnetic resonance imaging brain scans. Among the autistic participants, 15 had a co-occurring diagnosis of social anxiety.
The brain scans provided evidence that social anxiety in autism is associated with structural changes in the brain. Autistic participants with social anxiety possessed larger amygdala volumes than both the autistic participants without social anxiety and the non-autistic control group. The brain sizes of autistic adults without social anxiety did not differ from those of the non-autistic adults.
Just as in the behavioral study, this enlarged amygdala volume was specifically associated with social anxiety. The researchers did not find similar brain differences in autistic participants who had depression or generalized anxiety. In fact, these findings suggest that combining autism and social anxiety creates a unique biological signature that is not found when looking at autism alone.
When the researchers combined the data from the behavioral task and the brain scans, they found a connection between the two. Autistic individuals with larger amygdalas tended to display more acquiescent, lower-power behaviors during the role-playing game. This suggests that the physical structure of the amygdala and the tendency to yield control in social situations are closely linked features of social anxiety in autism.
Interestingly, participants who yielded power did not report feeling a lack of power. “One striking finding was that behavioral differences emerged during the social task even though participants’ own perceptions of their relationships during the task did not differ according to social anxiety,” Hao said. “In other words, autistic adults with social anxiety behaved more acquiescently without necessarily perceiving the interaction differently.”
As with all research, there are some caveats. The study design makes it impossible to definitively know how these brain and behavioral differences develop over time. Because the research measured participants at a single point in their lives, it is not known whether yielding social power leads to social anxiety, or if social anxiety causes individuals to avoid asserting dominance.
“The brain findings reflect group-level associations and should not be interpreted as a diagnostic marker for any individual,” Hao cautioned. The neuroimaging sample sizes were also relatively small, and the participants generally had high levels of education and intelligence test scores, which means the results might not apply to all autistic individuals.
“We also want to understand how experiences involving social ambiguity, unequal power, or interpersonal victimization contribute to social anxiety over time,” Hao said. Future research tracking people over several years could help clarify how the amygdala changes as these dynamics unfold.
“Ultimately, this work could inform autism-specific interventions that strengthen boundary-setting, assertive communication, and confidence in navigating social situations,” the researcher concluded. “It is equally important to create social environments that are more predictable, inclusive, and responsive to autistic people’s needs.”
The study, “Autism with social anxiety is associated with acquiescent behaviors and enlarged amygdala volume,” was authored by Yu Hao, Sarah M. Banker, Matthew Schafer, Ember Zhang, Sarah Barkley, Jadyn Trayvick, Arabella W. Peters, Abigaël A. Thinakaran, Christopher McLaughlin, Xiaosi Gu, Jennifer H. Foss-Feig, and Daniela Schiller.