For the first time, researchers from the Queensland Brain Institute have demonstrated that mild stress can trigger post-traumatic stress disorder (PTSD) in mouse models of autism spectrum disorder (ASD).
The study, published in iScience, reveals a reciprocal relationship between the two disorders, showing that individuals with ASD may be more prone to PTSD. That traumatic memory can worsen core autism traits.
Understanding the Autism Spectrum Disorder -PTSD Connection
Although previous studies have noted the co-occurrence of ASD and PTSD in humans, the biological link between the disorders has remained poorly understood. Researchers Dr. Shaam Al Abed and Dr. Nathalie Dehorter set out to investigate this connection by analyzing the impact of stress on ASD mouse models.
“We demonstrated in four mouse models of ASD that a single mild stress can form a traumatic memory,” Dr. Al Abed explained.
By contrast, in non-ASD (control) mice, PTSD only developed after extreme stress, highlighting a unique perception of stress in ASD that leads to the formation of PTSD-like symptoms.
How Stress Alters the Brain in ASD
The study found that alterations in the prefrontal cortex—a brain region involved in social cognition and behavior—are responsible for this increased vulnerability to PTSD.
- The prefrontal cortex contains specialized interneurons that help regulate fear responses and process sensory information.
- In ASD, these interneurons respond abnormally to stress, causing an overactivation of the prefrontal cortex, which disrupts normal memory formation and leads to PTSD-like responses.
- This imbalance worsens ASD-related traits, such as difficulties with social interaction and emotional regulation.
“We didn’t anticipate that forming a traumatic memory would aggravate the social and behavioral difficulties in ASD,” said Dr. Dehorter.
Potential for Behavioral Therapy
Despite the concerning link between PTSD and ASD, researchers found a promising solution: behavioral therapy.
“When traumatic memories are successfully recontextualized using behavioral therapy, the ASD traits that worsened following stress dramatically improved,” Dr. Dehorter noted.
These findings suggest that awareness of PTSD predisposition in ASD could reshape how clinicians approach treatment, leading to more effective stress management strategies.
The study not only validates the strong connection between ASD and PTSD but also emphasizes the potential of behavioral therapy in improving outcomes for individuals with autism who experience trauma.
Reference: Alice Shaam Al Abed, Tiarne Vickie Allen, Noorya Yasmin Ahmed, Azza Sellami, Yovina Sontani, Elise Caitlin Rawlinson, Aline Marighetto, Aline Desmedt, Nathalie Dehorter. Parvalbumin interneuron activity in autism underlies susceptibility to PTSD-like memory formation. iScience, 2024.
