Newly published research in rodents and ongoing research in humans examines the effects of psychiatric drugs, including antidepressants, on the composition of gut bacteria.

Share on Pinterest Scientists are slowly discovering the effects that antidepressants have on various bacterial strains that usually live in the gut.

More and more studies are supporting the role of the gut microbiota in psychiatric conditions.

Anxiety and depression are only some of the mental health conditions that researchers have linked to changes in the composition of the gut microbiota.

For example, a recent study that Medical News Today has reported on listed a range of bacteria that contribute to creating neuroactive compounds in the gut — that is, substances that interact with the nervous system, influencing the likelihood of developing depression.

Other research in mice has shown that rodents bred to be germ-free develop symptoms of anxiety and depression and become socially withdrawn.

So given this intimate link between mental health and the composition of gut bacteria, do psychiatric drugs that affect mood also impact the population of bacteria in the gut?

Researchers led by Sofia Cussotto, from University College Cork, in Ireland, set out to investigate this in rodents. First, the team “investigated the antimicrobial activity of psychotropics against two bacterial strain residents in the human gut, Lactobacillus rhamnosus and Escherichia coli.“

The psychotropics that the researchers focused on included: fluoxetine, escitalopram, venlafaxine, lithium, valproate, and aripiprazole.

Then, the scientists tested “the impact of chronic treatment with these drugs” on the rats’ microbiota.

Cussotto and her team published the first part of their results last year in the journal Psychopharmacology. They have now presented their full findings at the European College of Neuropsychopharmacology Congress, in Copenhagen, Denmark.