Schizophrenia and the virome

Schizophrenia PET scan

Schizophrenia PET scan

Schizophrenia is a mental health disorder in which people cannot recognize reality, suffer from hallucinations, and experience social withdrawal.  The causes of schizophrenia are unknown, but it is thought to include genetic, environmental, psychological, and social risk factors.  As we have written about extensively in this blog, the bacteria and viruses in our body have an important connection to our brain and behavior, in what has been termed the ‘gut-brain axis’.  Considering the gut-brain axis, a team of scientists from Johns Hopkins University wondered if the microbiome, and specifically the virome, was somehow related schizophrenia.  They recently published their findings in Schizophrenia Bulletin.

The scientists sampled the throat microbiome from 74 people in the Baltimore, MD area, 41 of whom suffered from schizophrenia and 33 of whom did not.  They discovered that a specific bacteriophage (virus that infects bacteria), Lactobacillus phage phaidh, was linked to schizophrenia, which was found in 17 of the 41 schizophrenia patients, but only 1 of the 33 control individuals.  In addition, 9 of those 17 schizophrenics had a comorbid immune disorder, such as diabetes or Crohn’s disease, whereas only 2 of the remaining schizophrenics without the phage had these diseases.  The scientists also found a loose link between taking the drug valproate and occurrence of the phage.  Interestingly, this drug has been previously shown to affect the microbiome.  Finally, the existence of the phage coincided with higher levels of the bacteria that the phage attacks, Lactobacillus gasseri.  This is an unsurprising result because a phage and its target are usually found together.

The scientists acknowledge that the results of this study do not prove any real association between the microbiome and schizophrenia, but based on the results, they suggest that further research is warranted.  Notably, Lactobacillus gasseri is sometimes included in probiotics to supposedly relieve gastrointestinal issues.  However, if gasseri’s phaidh phage goes along with it, then according to this study, it may cause more harm than good.

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