Exposure to Trauma and Post-Traumatic Stress Symptoms Among Adults with Autism Spectrum Disorder

Background: Post-Traumatic Stress Disorder (PTSD) is the most common chronic stress disorder resulting from exposure to traumatic events. The first diagnostic criterion for PTSD is an exposure (direct or indirect) to actual or threatened death, serious injury, or violence (APA, 2013). In recent years, studies indicated that PTSD may also develop following bullying experiences (Nielsen et al., 2015). Previous research indicates that individuals with Autism Spectrum Disorder (ASD) are at increased risk of experiencing traumatic events and being significantly affected by them (Mandell et al., 2005). However, PTSD symptoms among individuals with ASD and the nature of the traumatic events have yet to be sufficiently studied.

Objectives: The main aim of this study was to examine PTSD symptoms among high-functioning adults with ASD and typically developing controls, following various potentially traumatic life events, such as serious accidents, life-threatening illness or injury, and a wide range of negative social events.

Methods: Fifty adults, 25 (15 males) with a formal ASD diagnosis and 25 (15 males) with typical development (TD), matched on age and gender, took part in the study. Participants completed several self-reported on a comprehensive list of potentially traumatic life events that included “classic” traumatic events (based on the Life Events Checklist for DSM-5; Weathers et al., 2013) and negative social events (based on the bullying questionnaire; Sourander et al., 2010), and on PTSD symptoms with regards to the most significant traumatic event they chose from the list (PCL - PTSD Check List for DSM-5; Weathers et al., 2013).

Results: 32% of participants from the ASD group met the PCL cutoff for PTSD probable diagnosis, compared to only 8% in the TD group. Compared to TD participants, participants with ASD reported significantly more PTSD symptoms in general, and particularly more symptoms of hyper-arousal. Participants with ASD reported on more traumatic life events in general, and specifically more negative social events, compared to TD participants. Exposure to negative social events was related to PTSD symptoms among participants with ASD but not among TD participants. In contrast, exposure to “classic” traumatic events was related to PTSD symptoms among TD participants but not among participants with ASD. Moreover, 60% of participants in the ASD group chose a negative social event as the traumatic event, compared to only 24% of the TD group.

Conclusions: Compared to the TD group, participants with ASD were more exposed to traumatic life events and developed higher levels of PTSD symptoms following them. According to our results, the social field may be particularly traumatic for individuals with ASD. The higher level of exposure to traumatic events in the ASD group could also be related to the unique subjective perception of the event that may be influenced by cognitive, emotional and sensory characteristics. It is possible that PTSD is an under recognized co-morbid diagnosis in individuals with ASD, which required diagnostic and therapeutic attention.