Psychobiotics are probiotics that can lift your mood.

Studies have been difficult to interpret due to differing protocols.

New meta-analyses are attempting to quantify just how beneficial psychobiotics are to psychiatry.

“All life is an experiment. The more experiments you make the better.” –Ralph Waldo Emerson

“All life is an experiment. The more experiments you make the better.” –Ralph Waldo Emerson

The gut-brain axis has caught the attention of the world, revealing that our gut plays an intriguing role in our mood and cognition.

But just how large a role? We know that depression and anxiety have numerous causes, including genetics, bereavement, and environmental stress. Those are not microbial problems, but they share a lot of symptoms with a poorly balanced microbiome.

A few years ago, I wrote a book with two of the top researchers of the gut-brain axis, Ted Dinan and John Cryan. They coined the term psychobiotic to refer to substances like probiotics and prebiotics that improve mood and cognition. The book was titled The Psychobiotic Revolution, and it was published by National Geographic. We were all surprised when it became a bestseller. Apparently, we hit a nerve.

At the time, most of Cryan and Dinan’s studies were done in mice, specifically germ-free mice. These are perfect animals for this kind of research, because you could see how different the mice were without any microbes, and then you could introduce microbes to see what changes they made.

My editor and I were worried about the lack of human studies. We were ready to change the title to “What to Do With a........

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