Table 4. Summary of variables identified in selected studies.

ASD: autism spectrum disorder, SAD: social anxiety disorder, SASKO: social anxiety-social competence deficit scale, IU: intolerance for uncertainty scale

Author(s)	Country	Study characteristics	Population	Results
South and Rodgers 2017 [7]	United States and United Kingdom	The review-based study focuses on three aspects of ASD; atypical sensory function and anxiety, alexithymia and Mindfulness in ASD, and intolerance of uncertainty in ASD to suggest a model for future studies.	Youth and adults	The study suggests that the intolerance of uncertainty is an intermediate factor in the development of anxiety in social settings, which makes it hard for ASD individuals to live with ambiguity and find it challenging to identify whether, under each social circumstance, the same rules will be followed. This is also because ASD individuals are cognitively and behaviourally rigid, which relates to having repetitive and restricted behaviors. Other reasons that contribute to social anxiety include a lack of self-emotional awareness in complex situations.
White et al. 2014 [8]	United States	The study reviews to understand anxiety among people with ASD.	Children, adolescents, and adults	It is suggested that for anxiety in ASD, emotional regulation impairments are a risk factor. The ubiquitous link between emotional regulation impairments and ASD that stems from physiological, socio-cognitive, and neural mechanisms answers why individuals with ASD are at a higher risk of developing comorbid SAD.
Espelöer et al. 2020 [9]	United Kingdom	The study is based on a quasi-experiment design for ASD individuals (n=25; mean age: 38.8), non-clinical individuals (n=23, mean age: 44), and individuals in the reference group with SAD (n=68, mean age: 37). The authors measure differences in SASKO and IU scores among the groups.	18 to 65 years old individuals	The study finds that individuals in the ASD group scored significantly higher on social anxiety values of speaking and rejection than those in the SAD group. Furthermore, a deficiency in social competence, which includes deficits in interaction and difficulty in processing social information, is another factor that contributes to social anxiety among autistic individuals.
Meyer et al. 2006 [10]	United States and United Kingdom	The authors experiment on individuals with Asperger's syndrome (n=31) and typical development children (n=33) by examining children’s responses to hypothetical social vignettes, self-reported social difficulties, and psychological functioning measures. Interviews were also conducted with parents to gain detailed information on the clinical diagnosis of their children.	Children	The study found a systematic correlation between self-reported social anxiety by children and their parents' reports of impaired social competence. The study suggests that social information and attribution processing may be important factors to consider in understanding the emotional and behavioral difficulties experienced by children with Asperger's syndrome.
Jobe and White 2007 [11]	United States	The quantitative study uses a sample of 97 undergraduate individuals (mean age: 19.4) to measure characteristics of dating, friendship history, feelings of loneliness, and social motivation experienced by autistic individuals. The data was collected on a self-reporting basis through a survey-based questionnaire. The study measured a broader autism phenotype, which refers to a set of subclinical personality traits and symptoms associated with ASD. The study used the Autism-Spectrum Quotient to measure the broader autism phenotype in the participants.	College students	The study found that individuals with a stronger phenotype had romantic relationships of longer duration, in comparison to those with fewer ASD characteristics. The study also found that the total autism-spectrum quotient score was a valid predictor of loneliness, and the contribution made by the length of the current best friendship approached significance. However, there was a significant correlation between respondents with high autistic spectrum scores and the need for long-term romantic relationships. Preference for sameness and resistance to change are hallmark characteristics of ASD. There is a possibility that this plays a role in the tendency for individuals with stronger ASD phenotypes to maintain long-term romantic relationships.​​​​​​
Bejerot et al. 2014 [12]	Sweden	Researchers employed a comparative survey design, with three groups: individuals with ASD (n=50, mean age: 30 years), individuals with SAD (n=100, mean age: 34.6 years), and a comparative group including non-ASD (n=53, mean age: 32.3 years) people.	Adults	Even though individuals with ASD and SAD showed a high level of social anxiety, the reasons were different. The SAD group perceived themselves as being socially incompetent even though they acknowledged adequate social skills; however, people with ASD are more socially awkward and have poor social skills. The study also found that some ASD individuals often have less social anxiety due to their poor insight into how others perceive them.
Stark et al. 2023 [13]	United States	Based on a secondary data analysis, the research evaluates a sample of 194 participants with and without psychiatric disorders. It includes the measures related to autism spectrum symptoms, social anxiety symptoms, social competence, intelligence quotient, and socioeconomic status.	Children (8-13 years old)	According to the results, reduced social competence is a risk factor for social anxiety development among children with ASD, and the relationship between social anxiety and ASD is not solely attributable to measurement/item overlap.
White et al. 2015 [14]	United States	The study includes 15 participants with ASD and 18 (gender-matched) without ASD. The measures include brief fear of negative evaluation, social worries, social responsiveness, social communication, and gaze patterns.	Adolescents (12-17 years)	The study finds that adolescents with ASD, who are more cognitively able, are more like to have social anxiety. Negative evaluation’s self-reported fear among adolescents with ASD who are cognitively unimpaired explained a higher duration of gaze to social threat cues.
Briot et al. 2020 [15]	France	The research recruited 79 participants with ASD and 28 matched control participants. It screens anxiety disorders, psychiatric comorbidities, and depression using standard tools.	Children and adolescents; mean age = 11.51 years	A high risk for anxiety disorders is observed among individuals with ASD. Moreover, high social communication and motivation impairment levels indicate ASD and social anxiety (comorbid disorders).
Corden et al. 2008 [16]	United Kingdom	The study includes 21 individuals with a clinical diagnosis of Asperger’s syndrome. It also recruits 21 gender-matched healthy controls. The subjects completed various tests and tasks, including facial affect recognition, eye tracking, and a self-report measure of social anxiety.	Adults (M = 33.8 years) and controls (M = 32.1 years)	The study finds that, at recognizing fearful and sad facial expressions, the participants with Asperger’s syndrome performed significantly worse than the control group without Asperger's syndrome. However, it is also observed that perceptual or cognitive ability differences do not explain the sadness and fear recognition score’s variability. The participants with Asperger’s syndrome made significantly fewer fixations to the eyes, which affected their fear recognition ability. Findings conclude that the data supports an "amygdala hyperactivity" model that may explain the suggested lack of attendance to social stimuli in individuals with Asperger's syndrome.