A New Gut-Brain Connection: Obsessive-Compulsive Disorder

I continue to monitor any new research into the connection of the gut biome to “mental illnesses.”  My son, Alex, who is diagnosed with autism, suffers from terrible anxiety at times.  It’s heart breaking to see.  Obsessive compulsive disorder (OCD) is generally considered a subset of anxiety disorder – and it’s a nightmare for both the affected person and those who love him/her.

As my regular readers know, many so called psychiatric disorders are now associated with gut microbiome differences including, “…autism spectrum disorders (ASD), major depressive disorder (MDD), bipolar disorder, attention deficit hyperactivity disorder, post-traumatic stress disorder, psychosis and pediatric autoimmune neuropsychiatric disorder associated with streptococcal infections (PANDAS)/pediatric acute-onset neuropsychiatricsyndrome (PANS).”  I have written about all of these at one time or another on this blog.

A quick note then about a newly published paper.  Researchers in Australia and Canada have done the first gut biome study on obsessive compulsive disorder.  They sampled blood and stool from 21 patients with OCD (who were not on medications) and compared these samples to those from 22 control patients, who were not diagnosed with any kind of mental disorder.[i]  The findings were highly significant.

The patients with OCD had less gut bacteria diversity, and distinctly lower levels of 3 bacteria which produce the short-chain fatty acid, butyrate (Oscillospira, Odoribacter and Anaerostipes).  They also found signs of inflammation, in that blood levels of CRP (c-reactive protein) were highly elevated in the OCD group:  “CRP revealed moderate to strong associations with psychiatric symptomatology.”  That is, the higher the CRP level – the higher the level of inflammation in the person – the greater the OCD symptoms (and, not surprisingly, the greater the level of anxiety as well).

The authors point out the probiotics have shown in studies to reduce obsessive-compulsive scores.  In children with abrupt onset of OCD, as in the case of PANDAS or PANS, gut microbiome alterations have already been measured.   (See links above for more on these subjects.)

Butyrate, which I have mentioned many times before, is known have anti-inflammatory properties, as well as improving the integrity of the gut barrier (ie. preventing leaky gut):  “Increased intestinal permeability is one of the leading hypotheses for microbial dysbiosis in psychiatric conditions, as it permits translocation of intestinal contents into systemic circulation resulting in a potential inflammatory reaction.”

There is an extensive section in the paper pointing out areas for future research, as establishing that these differences exist is really just a first step.  There are no suggestions yet as to what to do about the problem.  We can only hope research into this progresses rapidly.


[i] Turna J, Grosman Kaplan K, Anglin R, et al. The gut microbiome and inflammation in Obsessive-Compulsive Disorder patients compared to age- and sex-matched controls: a pilot study [published online ahead of print, 2020 Apr 20]. Acta Psychiatr Scand. 2020;10.1111/acps.13175. doi:10.1111/acps.13175

One Comment on “A New Gut-Brain Connection: Obsessive-Compulsive Disorder

  1. Autism spectrum disorder: if you don’t already know about him, go to Ionbiome.com, Zack Bush, MD has a lot of wisdom for you (and anyone interested in their microbiome.)

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