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Were we wrong? Professor says depression may be caused by parasitic, bacterial & viral infections

For the last six decades, it’s been widely accepted that clinical depression stems from various combinations of biological, psychological and environmental influences---it’s treated as an emotional disease connected to the brain.

Scientists have also observed that the brains of people who suffer from depression are markedly different from those who do not.  

There are certain neurotransmitters, primarily serotonin, which tend to be deregulated for people who have clinical depression, also known as Major Depressive Disorder (MDD), but there aren’t many answers as to why these areas of the brain differ in depressed people.

Dr. Turhan Canli, an integrative neuroscience associate professor at Stony Brook University, has stirred up a bit of controversy in the science community after making claims that depression may have less to do with brain chemistry, and more to do with a viral or bacterial infection, the Huffington Post reported earlier this month.

In Canli’s research paper, published in the Biology of Mood & Anxiety Disorders journal, he proposes that depression is the result of the invasion of parasites, bacteria or viruses that enter the body and end up affecting the brain, resulting in mood and behavioral changes.

 Canli said that one of the largest symptoms in depressed people is inflammation, and that was one of his biggest clues.

While inflammation can come from many sources, looking at depression as a result of infection widened the realm of possibilities as to what its root cause could be.

In literature that Canli found regarding digestion, he discovered that over 1,000 strains of bacteria in our intestines needed to digest food can also be connected to our emotional state. People in a study who received a probiotic to improve their balance of good versus bad bacteria also reported better moods, a reduction in anxiety and a reduction in depression.

In another study conducted in over 20 European countries, Canli said a correlation was drawn between the T. gondii p parasite and suicide rates. The more instances of the parasite, the higher the national suicide rate. Canli is cautious in citing that study, emphasizing that it was correlation, not causation that was established from the findings.  

He also referenced animal based studies, including one where rats that were bred to have no intestinal bacteria were put under strenuous circumstances in labs and often responded with high stress levels. However, once they were put on a diet that included regular intestinal bacteria, their stress levels began to even out.  

About 10 percent of people in the U.S. suffer from depression, and up until this point, the discovery of deregulated neurotransmitters led to treatments like serotonin uptake inhibitors. However, Canli says when a patient complains to a psychiatrist about depression in the future, a solution may be administering a blood test to identify whether any microorganisms identified as biomarkers of depression are present, and treating the “invader” accordingly.

What do you think of Canli's findings?

LINKS:

http://www.huffingtonpost.com/2014/12/02/depression-infectious-dis_n_6172074.html?utm_hp_ref=healthy-living

http://www.biolmoodanxietydisord.com/content/4/1/10