Richard Horowitz, MD

Richard Horowitz MD

Why Can’t I Get Better?

Psychobiotics for the Psyche

Intestinal bacteria play an important role in brain health

Posted Dec 07, 2013

Many of the patients who come in to see me with the diagnosis of Lyme disease suffer from psychological symptoms, including depression, anxiety, and panic disorders. Sometimes they are diagnosed with OCD, PTSD, bipolar disorder, or even schizophrenia. That is because Lyme disease is the “great imitator”, mimicking every psychiatric diagnosis in an ICD-9 manual. These patients have usually gone to their primary care provider or psychiatrist with these complaints, and leave the office with an SSRI like Prozac, a benzodiazepine like Valium, or antipsychotic medication like Risperdal. We are trained as physicians and mental health providers to automatically go to our prescription pads and write out scripts for these chemical compounds that change our brain chemistry. Although this approach is effective in controlling symptoms, it does not always address the underlying cause of the problem. Is there another way?

Lyme disease is a multisystemic illness, caused by the bacteria Borrelia burgdorferi. One of the mechanisms through which this bacterium affects our body and causes symptoms is by the production of inflammatory cytokines. These are cell signaling messenger molecules, such as TNF-α, interleukin-1 (IL-1), and interleukin-6 (IL-6). These molecules are produced when our body is fighting the bacteria, causing an inflammatory response. The downstream effect of these cytokines are fatigue, joint and muscle pain, memory and concentration problems, and mood disorders. The medical literature contains extensive evidence on the occurrence of how these cytokines are linked to different disease processes, including congestive heart failure, pain syndromes, sleep disorders, as well as major depression and anxiety. How can we affect the production of cytokine levels in the body and influence mood?

New and exciting scientific research is showing a relationship between the gastrointestinal tract and the brain. The bacteria in our gastrointestinal tract, known as our microbiome, have an effect on the types of cytokines that we produce in our body. In my book, “Why Can’t I Get Better? Solving the Mystery of Lyme and Chronic Disease” I discuss in the gastrointestinal chapter that although there are hundreds of different species of bacteria in our G.I. tract, there are two major types of intestinal bacteria that are particularly important in cytokine production: lactobacilli and bifidobacteria. Most strains of lactobacilli are robust producers of the inflammatory cytokines such as TNF-alpha, where most strains of bifidobacteria are weak cytokine producers. Bifidobacteria are able to decrease the production of cytokines from lactobacilli, changing their immunological effects. It is therefore possible that by manipulating the types of intestinal bacteria, we can also affect cytokine production and change mood.

A recent study published in Biological Psychiatry, showed that probiotics may offer an alternative treatment option for depression and other psychiatric conditions. The journal's editors reported that healthy volunteers who received a type of probiotic called Lactobacillus helveticus R0052 plus B longum for 30 days reported significantly lower stress levels than those who received placebo. Another study of 124 volunteers (mean age, 61.8 years) showed that those who consumed probiotic-containing yogurt for 3 weeks had significantly improved mood compared with those who received placebo. That is because "as a class of probiotic, these bacteria are capable of producing and delivering neuroactive substances such as gamma-aminobutyric acid [GABA] and serotonin, which act on the brain-gut axis."

Manipulating the microbiome of the gut provides us with new therapeutic possibilities in medicine. We are already using fecal transplants to effectively treat resistant Clostridium difficile infections. Recent scientific studies have shown that we can transfer the gut bacteria from a lean healthy person into an overweight one with blood sugar difficulties, and help them to lose weight and improve glycemic control. Increasing the bifidobacteria in the gut may therefore be one novel way to reduce inflammation in the body and improve our mood and wellbeing. Food is also medicine. I look forward to the day when a patient will come into my office complaining of depression and anxiety and instead of pulling out my prescription pad, I will be telling them to “take two yogurts and call me in the morning”.

Dr Richard Horowitz

Dr Richard Horowitz is the author of the recently released book “Why Can’t I Get Better? Solving the Mystery of Lyme and Chronic Disease”, available through St Martin’s press.


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