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‘Millions’ with bipolar disorder could be helped by probiotics? Release pushes pure speculation

Probiotics could help millions of patients suffering from bipolar disorder

Our Review Summary

bipolar disorderThis news release focuses on a study of the gut microbiome, an emerging avenue of research. The release would have been better had it provided more detail about the study (including the number of patients involved) and the sizes of the beneficial effects. Instead, the release relies heavily on speculative language, suggesting a direct connection between gut inflammation or “microbial imbalances” and mood disorders. Despite a slew of recent studies, no causal relationship has been established between the microbiome and mental health.


Why This Matters

The microbiome, a compelling area of research, is sometimes presented in news releases and news stories as a new panacea for a wide range of health conditions. But what’s currently unknown in this area significantly outweighs what is known.

Writing about this new field of research requires an emphasis on caveats. News releases should avoid implying causality (ie. “good bacteria” or “a balanced microbiome” is responsible for good outcomes), and highlight study limitations.

As of 2018, and contrary to what this new release headline implies, probiotics have not been shown to help millions of patients suffering from any disease.


Does the news release adequately discuss the costs of the intervention?

Not Satisfactory

Neither the cost, composition, or dosing of the intervention — a probiotic preparation of strains of a Lactobacillus and Bifidobacterium — is provided.

Does the news release adequately quantify the benefits of the treatment/test/product/procedure?

Not Satisfactory

The release notes that the 6-month study yielded the following results:

The group randomized to receive the probiotic, on average, “didn’t return to hospital as quickly … required less in-patient treatment time … [and the] beneficial effects were most pronounced in those patients  who exhibited abnormally high levels of inflammation” when compared to the placebo group.

However no data are provided to support these outcomes. The news release should have included information about the number of patients in the trial, the schedule of probiotic dosing given to the participants, the changes in inflammation levels, the difference in number of rehospitalizations, and other details.

The release also includes some other unsubstantiated claims, such as:

  • probiotics “may reduce inflammation of the gut”
  • [gut inflammation] is known to exacerbate bipolar disorder
  • probiotics are “known to improve overall health of the host”

Does the news release adequately explain/quantify the harms of the intervention?

Not Satisfactory

The release doesn’t mention any potential harms of probiotics nor the fact that they are not regulated for safety and effectiveness.

Does the news release seem to grasp the quality of the evidence?

Not Satisfactory

The release doesn’t describe the study parameters. According to the abstract, it was a double-blind randomized comparison of 33 people on probiotics after discharge for a manic episode, and 33 patients who took placebo.

The study had some limitations that should have been mentioned in the release. First, the drop-out was high with only 79% (n=52) of the original group completing the 6-month follow-up.

Second, all the subjects continued to take their usual medications and these were not standardized. Therefore, some of the differences noted could be attributed to medications, not the intervention.

Finally, no conclusions regarding the role of “inflammation” in modulating behavior can be drawn since inflammatory measurements were not taken in the gut or the cerebrospinal fluid.

Does the news release commit disease-mongering?


The release doesn’t engage in disease mongering. It provides context on the prevalence of bipolar disorder in the US.

Does the news release identify funding sources & disclose conflicts of interest?

Not Satisfactory

Funding is not mentioned.

A version of the study published in April 2018 noted that the lead author had no conflicts of interest to disclose.

Does the news release compare the new approach with existing alternatives?


The news release mentions the standard treatments for bipolar disorder:

“Currently, the standard treatment (of bipolar illness) includes a combination of psychotherapy and prescription medications such as mood stabilizers and antipsychotics.”

Does the news release establish the availability of the treatment/test/product/procedure?

Not Satisfactory

The dosage and composition of the probiotic mixture used in this study are not clarified. Therefore, readers have no idea if just any probiotic will do. This is worrisome since some readers — particularly those with bipolar illness — may extrapolate from the news release headline and start self-medicating based on these preliminary findings that don’t prove probiotics help bipolar illness.

Does the news release establish the true novelty of the approach?

Not Satisfactory

While the use of probiotics to treat bipolar disorder is part of an “an emerging field of research” and therefore novel, it hasn’t been established through this or other research as an effective intervention.

The release implies that the study builds on previous research in this area. In that case, it would have been helpful for the news release to disclose those aspects of the study had been previously published.

Does the news release include unjustifiable, sensational language, including in the quotes of researchers?

Not Satisfactory

Along with the unsubstantiated headline suggesting “millions” of people who suffer with bipolar disease could be helped by probiotics, the release employs the pseudoscientific term “gut-brain axis” to suggest there are known connections between good and bad bacteria, microbial balance, and psychiatric mood disorders.

But without data, much of the language used throughout the news release is unjustified.

Total Score: 2 of 10 Satisfactory


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