Recent literature has suggested that individuals with autism spectrum disorder (ASD) or autistic traits (ATs) would be more likely to encounter traumatic events in their lifetime and to develop post-traumatic stress disorder (PTSD). However, the nature of this relationship has not yet been fully elucidated. The aims of this study were to evaluate the relationship between AT and PTSD and to investigate which specific autistic dimension was more associated with trauma and stress-related symptoms.

A total of 68 subjects with ASD and 64 healthy controls (HCs) were assessed with the Adult Autism Subthreshold Spectrum (AdAS Spectrum) and the Trauma and Loss Spectrum (TALS) questionnaires. Statistical analyses included Mann–Whitney U test, chi-square test, calculation of Spearman’s coefficients, and logistic regression analysis.

Patients with significant AT reported a 30% rate of PTSD and higher TALS total and domain scores than HCs, among whom no PTSD was found instead. Significant positive correlations were reported between AdAS Spectrum and TALS-SR scores in the whole sample. AdAS Spectrum total scores were statistically predictive of the presence of PTSD. High scores at AdAS Spectrum Hyper-Hyporeactivity to sensory input and Restrictive interest and rumination domains were identified as positive predictors of a probable PTSD.

Compared to HCs, subjects with significant AT are more likely to present symptoms of PTSD. In particular, AT related to ruminative thinking, narrow interests, and sensorial reactivity would seem to predict the presence of post-traumatic stress symptomatology.