The Role of Probiotics in Mental Health
In 1950, at Staten Island's Sea View Hospital, a group of patients with terminal tuberculosis were given a new antibiotic called isoniazid, which caused some unexpected side effects. The patients reported euphoria, mental stimulation, and improved sleep, and even began socializing with more vigor. The press was all over the case, writing about the sick "dancing in the halls tho' they had holes in their lungs." Soon doctors started prescribing isoniazid as the first ever antidepressant. The Sea View Hospital experiment was an early hint that changing the composition of the gut microbiome — in this case, via antibiotics — might affect our mental health. Yet only in the last two decades has research into connections between what we ingest and psychiatric disorders really taken off. In 2004, a landmark study showed that germ-free mice (born in such sterile conditions that they lacked a microbiome) had an exaggerated stress response. The effects were reversed, however, if the mice were fed a bacterial strain Bifidobacterium infantis, a probiotic. This sparked academic interest, and thousands of research papers followed.
@miraj We humans have about 100 trillion microbes residing in our guts. Some of these are archaea, some fungi, some protozoans and even viruses, but most are bacteria. Things like diet, sleep, and stress can all impact the composition of our gut microbiome. When the microbiome differs considerably from the typical, doctors and researchers describe it as dysbiosis, or imbalance. Studies have uncovered dysbiosis in patients with depression, anxiety, schizophrenia, and bipolar disorder.