If I had a cardboard box for a head I’d be sad too.

“Rumination refers to the tendency to repetitively think about the causes, situational factors, and consequences of one’s negative emotional experience. Basically, rumination means that you continuously think about the various aspects of situations that are upsetting. Think about your own tendencies. When something upsets you do you tend to mull on it, and keep going over the problem again and again? If so, then you are probably a ruminator…The research is extremely consistent. People who ruminate are much more likely to develop problems with depression and anxiety, and those problems are hard to overcome for someone who fails to change ruminative thought patterns. Rumination is also connected to many different forms of self-sabotage. For example, if you ruminate on something upsetting a friend did, it’s going to take longer to forgive that friend and get back to enjoying time spent with him or her. If you hold a grudge and constantly ruminate on what that friend did, you might even destroy a good friendship.” (1)

Edward A. Selby Ph.D.


As this quote makes clear, replaying negative events over and over and over again in your head can quickly turn an appropriately sad mood into full-blown depression. Through negative self-talk, unfortunate events are often interpreted by ruminators as proof of their inherent unworthiness. Dr. Aaron T. Beck, father of Cognitive Behavior Therapy (CBT), calls the emotional outcome the four D’s: Defeated, Defective, Deserted and Deprived.

A large part of modern psychotherapy is involved in helping depressed clients forcefully dispute the negative thoughts that precede these feelings. Albert Ellis, the father of Rational Emotive Behavior Therapy (REBT) which is a precursor to CBT, made it his life’s work to counter these irrational beliefs.

In his classic book How To Stubbornly Refuse To Make Yourself Miserable About Anything-yes, Anything, Dr. Ellis wrote:

“Now let us suppose that when you are unfairly deprived of a job or a loan you make yourself feel severely anxious, depressed, self-denigrated, or enraged. You see that you are being treated unfairly. You upset yourself immensely about their unfairness. Can you still choose to have or not have these strong, off-the-wall feelings? Definitely, yes. Clearly, you can.

That is the main theme of this book: No matter how badly you act, no matter how unfairly others treat you, no matter how crummy are the conditions you live under—you virtually always (yes, A-L-W-A-Y-S) have the ability and the power to change your intense feelings of anxiety, despair, and hostility. Not only can you decrease them, you can practically annihilate and remove them. If you use the methods outlined in the following chapters. If you work at using them!”

And I agree, as does the clinical research. How you interpret the unpleasant realities of your life can and does affect how you feel about them. I believe everyone would be well served learning these techniques to make it through life without losing precious sanity.

That said, there has always been some dispute about the assumptions made by proponents of both REBT and CBT. In both causality is chiefly assumed to occur in this manner:

A → B → C

Where (A) represents the event we do not desire, (B) the belief or beliefs we tell ourselves about this unpleasant experience and (C) the emotional and behavioral consequences that flow from that interpretation.

Some have questioned this unidirectional model pointing instead to disturbances in neurotransmitter pathways that lead to negative thoughts not necessarily tied to changes in external reality. The controversy rages between those who emphasize the use of mind-altering pharmaceuticals to control debilitating mood disorders in contrast to those who champion the use of talk therapy based on either REBT or CBT principles.

Today’s study suggests that gut flora plays a crucial missing link in how negative thoughts are initiated. (2) Its results suggest that both psychology and psychiatry need to move beyond talk therapy and the manipulation of neurotransmitters and focus more of their attention on the state of human gut flora.


Forty young adults were chosen to participate in the study. Their mean age was about 20.

Eight were men, thirty-two female. None were reported to have cardiovascular, kidney or liver disease.

Neither were they reported to suffer from allergies or intolerance to either lactose or gluten. No one reported being on any medication or drinking more than three to five alcoholic drinks per week.

All were quizzed with the Mini International Neuropsychiatric Interview (M.I.N.I.). This is a short interview to screen for several psychiatric disorders. All were found to be free from these disorders and none reported having a family history of depression or migraines.

This is important because the researchers wanted to study the effects of probiotics in people free from known psychiatric disturbances. Most studies of this type are done with people already suffering some form of mental imbalance so the results of this study have much wider implications.

Participants were randomized into two groups, one receiving a daily placebo and the other a daily probiotic for four weeks. The probiotic was Ecologic® Barrier produced by Winclove, a company headquartered in the Netherlands.

The probiotic contained the following bacterial strains: Bifidobacterium bifidum W23, Bifidobacterium lactis W52, Lactobacillus acidophilus W37, Lactobacillus brevis W63, Lactobacillus casei W56, Lactobacillus salivarius W24 and Lactococcus lactis (W19 and W58).

This was a triple-blinded trial meaning that the participants, administrators and the assessor of results had no ideal which of the participants received the probiotic versus placebo.

Before and after the intervention, all participants filled out a questionnaire to assess their reactivity to sad mood. They were also assessed for symptoms signalling depression and anxiety.


In order to save me some time, I’ll let the researchers speak for themselves:

“The aim of the current study was to investigate the effect of a multispecies probiotic intervention on cognitive reactivity in healthy individuals not currently diagnosed with a mood disorder. As mentioned in the introduction, cognitive reactivity is an important vulnerability marker of depression; the content and the type of thoughts that are activated when an individual experiences sad mood predicts whether the sad mood will be transient or will persist, and predicts the development of clinical depression…We found that a 4-week multispecies probiotic intervention reduced self-reported cognitive reactivity to sad mood, as indexed by the LEIDS-r [The LEIDS-r is a thirty-four item questionnaire that assesses the extent to which a sad mood reactivates negative thought patterns].

Further analyses showed that the strongest beneficial effects were observed for the aggression and rumination subscales, indicating that in the probiotics supplementation condition participants perceived themselves to be less distracted by aggressive and ruminative thoughts when in a sad mood. Notably, studies have shown that the tendency to engage in ruminative thoughts is sufficient to turn mood fluctuations into depressive episodes, and that individuals who typically respond to low mood by ruminating about possible causes and consequences of their state have more difficulties in recovering from depression…Further, the activation of aggressive thoughts has been associated with suicidal ideation and attempts…In sum, the present results indicate, for the first time, that probiotics intervention can influence cognitive mechanisms that are known to determine vulnerability to mood disorders.

–A randomized controlled trial to test the effect of multispecies probiotics on cognitive reactivity to sad mood.

Folks, this is huge!

Here we have a randomized, placebo-controlled trial demonstrating that daily intake of a probiotic can prevent rumination and feelings of aggression in otherwise healthy twenty-year old adults. And this all occurred without psychotherapy or the use of powerful psychiatric drugs.

Now, the researchers did note a few limitations of their study. First, they did not control for diet or the consumption of other probiotics or fermented foods during the study. But given that no one knew whether they were receiving a placebo or not, I’m not overly concerned that this confounded the results.

A second limitation of this trial was that probiotic intake was not independently verified by stool analysis, although I again see no reason why those randomized to the probiotic would have avoided taking it.

A major limitation of the study in my mind, and one readily acknowledged by these researchers, was the predominantly female composition of the participants. Recall that out of the forty people who took part in the study, only eight were men. It would be great to see a similarly constructed study done with a bigger male cohort to verify mood improvement in a larger group of men.

These results mimic what I’ve experienced in my life. Consistently taking probiotics calms me down making me far less anxious or prone to depressive thoughts.

I’m much less likely to “what if” myself to death about events that I have no control over. I’m also more likely to shrug off perceived slights. Rather than enrage myself over an inconsiderate driver cutting me off in traffic, I’m more likely to just ignore it and drive on.

I suspect one of the major reasons for these effects is that beneficial bacteria prevents endotoxemia and the initiation of the Inflammatory-Cortisol Ballet. Chronic inflammation fueled by gut dysbiosis has system-wide effects on all bodily processes, including the brain.

Does this mean that talk therapy is useless? Not at all.

I believe learning the lessons of Rational Emotive Behavior Therapy or Cognitive Behavior Therapy makes life far more bearable than would otherwise be the case. But this type of research is increasingly demonstrating how essential healthy gut flora is to preventing mood disorders.

It’s not an either/or issue. Actively disputing irrational beliefs AND having healthy gut flora is a winning combination to help deal with “the slings and arrows of outrageous fortune.”



15 Thoughts on “Do Probiotics Help With Depression? Research Says Yes!

  1. Jim on 10/29/2015 at 11:47 am said:

    Great post!

    I experienced huge improvements in mood when I started taking probiotics. I take Renew Life, but the 30 billion CFU count as it’s cheaper than the 50 billion count product.

    I never had an issue with depression or anxiety, but I would often fall into a funk before I started taking probiotics. Whenever I anticipate being in a stressful situation (holidays anyone?) I take extra.

    Ray, my probiotic doesn’t have the exact same bacteria as what was used in this study. Do you think it makes a difference?

  2. rjmedina on 10/29/2015 at 11:53 am said:

    Hi Jim,

    Thanks for visiting. I’m happy to hear about your experience.

    I think you answered your own question. The fact that you feel better is really all you need to know. I think any multi-species probiotic would work, although I’m sure some work better than others depending on the individual.

    Another way to gauge the effectiveness of a probiotic is sleep quality. If your sleep improves, that’s a good indication you’re taking the right one. It’s for this reason I always recommend that people take their probiotic before bedtime rather than first thing in the morning.

    • Jim on 10/29/2015 at 12:01 pm said:

      One other question. I use your Syontix prebiotic and was wondering if you have reconsidered your decision to stop making it. It really helps me stay regular and I like the fact that it isn’t full of fructose like some others.


      • rjmedina on 10/29/2015 at 12:13 pm said:

        First, let me say thank you for being a customer.

        I don’t think so. When I added up all the expenses involved in making and distributing the prebiotic, I was only netting 56 cents per bottle. Not exactly worth the effort or risk in such a sluggish economy.

        You may want to check out the Swanson prebiotic on the “Products I Recommend” page. It gets good reviews and I believe it’s also made from chicory grown in Belgium.

  3. Jeff on 10/29/2015 at 1:14 pm said:

    Great post! I have found definite changes in my mood and personality with both pre/probiotics and some vitamin supplements. B vitamins, specifically B2, are very disruptive. Probiotics seem to do the opposite. I have been taking a multispecies probiotic with some success, but it wasn’t until I added Reuteri and additional prebiotics that I noticed the difference. I became much calmer and I didn’t obsess about the little things. Like you said, less anxious. I have some OCD tendencies and I notice those going away when I hit the right combination. Sleep improves too. It’s not 100%, but I find these mood changes to be a better indicator of the right combinations of supplements than reduced bloating.

  4. rjmedina on 10/29/2015 at 1:28 pm said:

    Jeff, thanks for sharing your experience. Peace of mind is a real treasure.

    Yes, L. reuteri is a very important commensal so I’m not surprised you were helped by it. Also glad you mentioned prebiotics because keeping beneficial bacteria fed is also important.

    I know for a fact that I would never have attempted writing a blog before I corrected my gut dysbiosis only because my sour mood would have talked me out of it. Now, instead of hearing a little voice in my head saying “What if no reads your blog? Wouldn’t that be just awful?” I’m more apt to hear “So what if no one reads your blog? It’s not the end of the world.”

    Gut flora rocks!

    • Jeff on 10/29/2015 at 2:18 pm said:

      “Peace of mind”. I tried meditation a few years ago. I would describe these feelings in similar terms to what I felt immediately after a meditation session. Aware, but not anxious.

  5. David on 10/29/2015 at 3:15 pm said:

    Interesting! I have been on a variety of probiotics over the last few months and noticed definite changes in mood. The most obvious is when driving. Sometimes I am calm and relaxed. Other times I am itching to get on and wishing that car in front would go faster. This difference was quite noticeable, and I was really aware of it. If only I had noted when this happened, I might have been able to identify the probiotic I was taking at the time.

    To add a little more, for years I was irritable, depressed, negative about people. For the last 12 months I have been following the GAPS diet, and taking probiotics and fermented foods. Overall, my mood is significantly better, although there are occasional relapses. I think I am a ruminator, and one way I have dealt with the negative aspects of this is to avoid situations and people who I know irritate me. Unfortunately, this has cut me off from a lot of good aspects of my life, but overall I am feeling much better just concentrating on what I want to do.

    One thing I wonder about in the study is how probiotics help. Say a person had poor gut bacteria initially. One could see that adding probiotics to improve the quantity/mix of bacteria could help. But if the person had a good microbiome already, would the probiotics work their magic? Would the person have been less prone to depressive situations just because their gut bacteria were healthy? And could adding the probiotics actually knock it out of balance and produce other effects?

    • rjmedina on 10/29/2015 at 3:59 pm said:

      Hi David, thanks for sharing. There seems to be a theme developing here 🙂

      We still don’t know what is really behind all of this. As typical twenty somethings, I imagine all were eating a standard Western diet that would include plenty of omega 6 PUFAs, processed foods, alcohol, artificial sweeteners, gluten and dairy-based foods, etc. with the latter two precipitating into opioid peptides when eaten. We know that beneficial gut flora can counteract the effects of a bad diet in many different situations including high-fat feeding.

      Recall that in this post, the addition of inulin to pasta improved markers for intestinal permeability in otherwise “healthy” young men. Eating pasta was causing an apparent up-regulation of zonulin expression and consequent disruption to tight junctions. But it wasn’t enough to affect health markers, at least not noticeably at that age.

      I find many people can get away with an unhealthy gut flora and diet until about the age of 30 or so, although it’s different for everyone. That’s when things start heading South if left untreated.

      I guess what I’m getting at is that the absence of psychiatric disturbances in these participants isn’t proof that there is no room for improvement in diet or gut flora. Given the multi-generational exposure to antibiotics, alcohol, environmental toxins, cigarettes, bottle feeding, C-sections, processed foods, etc., I question whether anyone’s microbiome, at least in the industrialized world, is truly healthy.

      As to your last question, I wouldn’t believe so. The probiotics available for us to take comprise just a fraction of the 1,000 or so species in a healthy gut. They act as key species that help support other friendly constituents of the gut. I liken them to large trees in a rain forest. They help provide the environment for other beneficial species to flourish, but they are by no means the entirety of the forest.

  6. Darcie on 10/29/2015 at 8:54 pm said:

    Hi Ray….love your blog.

    Per your last comment: What’s wrong with eating dairy and also what is considered high-fat feeding? I’m pretty sure a long term high fat diet will alter gut flora, but what about occasional incidents?

    I’ve tried lots of different brands of probiotics over the last 5 years. Some supplements can cause constipation for me and others seem to cause insomnia. I’m still trying to figure out which specific species are responsible, not an easy task when they’re in blends.

    Btw, I brought your Syontix brand to Mexico with me (two years ago) and took it every single evening of my trip. All of my travel mates caught some sorta bug and had diarrhea, but not me. YAY!!!

    • rjmedina on 10/29/2015 at 9:12 pm said:

      Hi Darcie,

      The issue with dairy is with the type containing A1 casein protein that produces an opioid called beta casomorphin 7 upon digestion. I first covered that topic in this post and more recently here. All opioids affect gut motility for the worse and there is evidence from rodent studies that beta-casomorphin 7 can increase inflammation in the colon as evidenced by elevation of a marker called calprotectin.

      Milk protein is most abundant in milk and cheese but is not typically present in cream or butter. I recommend that people use milk from A2 casein sources like milk from Jersey cows or goat’s milk.

      As for high-fat feeding, I was referring to rodent studies in which they feed the little critters ridiculous amounts of fat to study the effects on their health. Even in these extreme circumstances, supplementing with either probiotics or prebiotics does a remarkable job of countering the ill effects of such an extreme diet.

      Glad to hear you survived Mexico and thanks for being a customer! That’s a great story although not for your mates:-)

      Have you tried either one of the probiotics on this page? I take the Renew Life and it works great for me although it might not for you. You’re right that it can be hard to determine which strains might be causing you issues, but please don’t give up looking for an effective probiotic.

  7. Maggie on 11/02/2015 at 1:51 pm said:

    Hi Ray,

    First I wanted to tell you how important your blog has been to me in figuring out how to get well again. I am adding my comments to this particular blog post as it is very pertinent to my health issues. About eight years ago, I stopped sleeping and started suffering daily constant anxiety. Of course that made me depressed. I thought I’d tried everything. I never connected my years of constipation, my inflamed joints, my white tongue, my thyroid antibodies, and the insomnia and anxiety to gut dysbiosis. (duh) Finally, finally, reading all your blog posts, starting probiotics, I have begun to get better. I am hopeful for continued recovery.

    To my point: I have experienced a dramatic reduction in anxiety just by taking probiotics. I’m sleeping much better as well, although not perfect yet. I am taking the Renew Life Critical Care (room temperature strain) and I guess I should experiment with some others to see if I can improve further. I have no idea if the refrigerated variety is better. I am also taking your prebiotics, and have long-ago made the diet modifications you discuss (gluten, dairy, PUFA, legumes, etc).

    I very much appreciate your blog, your insights, and your experiences. I am hoping you will continue opening up the comments section so I can glean additional information from others’ experiences as well.

    Please do not stop the blogging. You have saved a life!

    • rjmedina on 11/02/2015 at 2:58 pm said:


      Thanks for sharing your story and for your kind comments. Hearing that I’ve made a difference in someone’s life is very gratifying for me.

      Yes, I’ve decided to keep comments open from this point forward. I have a lot of very knowledgeable subscribers and I want them to be part of a community where we can all help each other get well and stay well.

  8. fawnie goodtiger on 11/05/2015 at 2:31 pm said:

    YES X1000. After taking several courses of a probiotic (Elixa), and now taking L. reuteri daily, my mood has improved. I’m able to deal with minor annoyances now without them escalating into major ones.
    My gut was wiped out after a surgery involving multiple courses of broad spectrum atb, steroids, opioids, and proton pump inhibitors (orthopedic surgery), and 6 weeks later I developed C.Dif, kidney stones and hydronephrosis >>> MOAR antibiotics, and opioids for THAT! I asked my doctors (one was an Infectious Disease doctor, another was a Gastroenterologist) if I should take probiotics/if that would help. Their answers? >> “Sure I guess it couldnt hurt” !!!
    Taking probiotics has helped my mood and my health. Appreciate your taking the time to address this!

    • rjmedina on 11/05/2015 at 3:19 pm said:


      Thanks for commenting. I love the response from your doctors. You’d think they could spend some time on PubMed doing some basic research on gut flora seeing how it’s increasingly difficult to ignore the avalanche of peer-reviewed research papers on the topic.

      Anyway, it’s great to hear that probiotics have helped your mood and health!

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