Brain Inflammation and Its Role in Repetitive Behaviors in Autism and OCD

Recent research has shed light on the connection between brain inflammation and repetitive behaviors commonly observed in individuals with autism spectrum disorder (ASD) and obsessive-compulsive disorder (OCD). The study, conducted by a team at the Daegu Gyeongbuk Institute of Science and Technology, has identified a molecular mechanism whereby chronic inflammation in the brain triggers overactivity of specific receptors, leading to repetitive, seemingly meaningless behaviors.

The team focused on microglia, the immune cells in the brain, which when activated due to a mutation in the NLRP3 gene, cause a sustained inflammatory response. This prolonged inflammation results in the overactivation of NMDA glutamate receptors, critical for excitatory neurotransmission. As these receptors become overactive, behaviors such as compulsive checking or washing may escalate. The study's findings suggest a causal link between brain inflammation and these behaviors.

To verify this, researchers administered memantine, a drug approved for Alzheimer's treatment, to the affected mice. The results were promising, showing a significant reduction in repetitive behaviors and normalization of glutamate receptor activity. Additionally, they found that the inflammatory cytokine interleukin-1 beta (IL-1β), released by inflamed microglia, plays a role in stimulating the overactivation of glutamate receptors. Blocking IL-1 receptors with a drug called anakinra suppressed receptor overactivity and eliminated repetitive behaviors.

This research highlights promising new avenues for treatment. Because memantine and anakinra are already FDA-approved for other conditions, they could potentially be repurposed for ASD and OCD, offering a faster and more cost-effective approach to therapy. Professor Jiwon Um emphasized that targeting brain inflammation might be an effective way to treat symptoms associated with these disorders, especially repetitive behaviors.

The study has been published in the journal Cell Reports and adds significant insight into the neuroinflammatory mechanisms underlying certain behavioral disorders. It underscores the importance of considering inflammation as a potential contributor to neuropsychiatric conditions and opens pathways for further exploration of anti-inflammatory treatments in managing ASD and OCD.