A quarterly publication of the Autism Research Institute

The Autism Research Review International is quarterly publication of the Autism Research Institute

Spring, 2016 | Number 2, Volume 30

Self-injurious behavior may not stem from pain insensitivity

A large number of children with autism spectrum disorders (ASD) exhibit self-injurious behavior (SIB). A new study casts doubt on the prevailing theory that these children are insensitive to pain, instead suggesting that the opposite may be true. 

James Bodfi sh and colleagues evaluated 30 adolescents with ASD and cognitive impairment and 41 with ASD only. They found that 63% of the participants with ASD and intellectual disability exhibited SIB, compared to only 24% of the participants with ASD only. Participants with intellectual disability also exhibited more severe SIB. 

The researchers then compared 34 adolescents with ASD and severe SIB to 17 with ASD only, taking skin samples to evaluate epidermal nerves and saliva samples to analyze biological markers associated with pain and stress. In addition, they tested the participants’ responses to sensory stimuli including heat, cold, pinprick, and deep pressure, evaluating their facial responses to these stimuli. 

The researchers report that the participants with SIB exhibited a significant increase in nonverbal responses to painful stimuli. “We also saw marked differences in nerve morphology in terms of density and distribution between the two groups,” Bodfish says. In addition, the researchers detected changes in immune system markers in the SIB group indicating heightened inflammatory response. 

“Taken together,” the researchers say, “our work suggests that at least a subgroup of individuals with chronic repetitive SIB may be in a physiological state similar to neuropathic pain/hyperalgesia associated with alterations in inflammatory, immune, and nociceptive [pain sensing] systems.”


Citations

“Severe self-injury in persons with autism and related neurodevelopmental disorders: Differences in sensory, autonomic, and immune markers suggest hyperalgesia,” J. W. Bodfi sh, M. Garrett, G. Wendelschafer-Crabb, W. Kennedy, and F. J. Symons, presentation to the May 2016 International Meeting for Autism Research (IMFAR).

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“Self-injury linked to altered pain processing in autism,” Pam Harrison, Medscape News, May 18, 2016