Association Between Autism and PTSD Among Adult Psychiatric Outpatients.

Purpose: Autism Spectrum Disorder (ASD) occurs in 1-1.5% of the general population and possibly in up to 20% of psychiatric outpatients. Post Traumatic Stress Disorder (PTSD) occurs at some point in life in 4% of the general population and in 14-20% of psychiatric outpatients. Knowledge about how PTSD manifests in people with ASD is important in order for it to be correctly diagnosed and intervened for.

Methods: This study investigated the relationship between PTSD and autism among adult psychiatric outpatients (N = 90) of whom 63 had ASD or subthreshold ASD based on DSM-5 criteria. The study group was subjected to in-depth psychiatric assessments using validated instruments. Diagnosis of PTSD was made based on the Mini International Neuropsychiatric Interview (MINI).

Results: There was a trend towards PTSD being more common among participants with ASD compared to participants without ASD, although significant differences could not be shown in this small sample. 21% of the ASD group had current PTSD, compared to 4% of the study group without ASD. There were no differences between the groups regarding exposure to trauma. There was a trend towards a relationship between number of autism symptoms and hyperarousal symptoms in PTSD. Conversely, the PTSD symptom of irritability/outbursts of anger, was significantly associated with number of autism symptoms.

Conclusions: A subgroup of psychiatric outpatients with ASD also suffer from PTSD. Hyperarousal symptoms are possibly more prevalent in the presentation of PTSD in individuals/patients with ASD compared to those without ASD.