Positive thoughts may boost the immune system according to research that suggests a link between the mind and our body’s natural defenses.
Scientists found that people who used positive thinking to boost activity in the brain’s reward system responded better to vaccination, with their immune systems producing more antibodies than others after getting the shot.
This work is not to be optimistic about the possibility of ridding people of diseases, but it does suggest that there may be mental strategies to help the immune system fight infections and even attack tumors to keep them at bay.
“It’s the first evidence in humans, in an apparently causal way, that if you learn how to recruit your reward system in the brain, the effectiveness of immunization increases,” said Talma Hendler, a professor of psychiatry and neuroscience at Tel Aviv University.
Previous work has shown that positive expectations can benefit patients with certain medical problems, as seen in the placebo effect. While animal studies suggest that activating the brain’s reward system can boost immune defenses, the picture in humans has been less clear.
in the studyHealthy volunteers participated in brain training sessions, where they tried different mental strategies to boost activity in specific parts of the brain. They knew how well they performed thanks to real-time feedback in the form of scores that rose in line with brain activity.
After four training sessions, the volunteers were given the hepatitis B vaccine. They were then given blood after two and four weeks, which the researchers analyzed for antibodies against hepatitis.
Scientists found that people who had enhanced activity in a part of the brain’s reward system called the ventral tegmental area (VTA) had the strongest immune response to the vaccine. Those who successfully reinforced it did so through positive expectations, or imagining good things happening.
This effect may be useful in boosting patients’ immune systems, but larger trials are needed to show whether there is any clear medical benefit. Co-author Dr Tamar Koren said the team was investigating whether other parts of the immune system were also affected, such as those responsible for inflammation.
“The approach we tested is only intended to be a complementary tool that may enhance the immune response to vaccination,” said Dr. Nitzan Lupianker, one of the study’s senior authors. “It cannot, and is not intended, to replace vaccines or standard medical care.”
Jonathan Kipnis, a professor of pathology and immunology at Washington University in St. Louis, agrees. “It may be too early to draw conclusions about the degree of clinical significance,” he said. “If such effects are proven to be clinically significant in a larger clinical trial, they will likely be complementary to existing treatments.”
Jeremy Howick, professor of compassionate healthcare at the University of Leicester, said the effect was small, and he cautioned that sick patients at the clinic might respond differently, but he still saw positives. “Given that healthcare professionals have the right to say things that can generate positive expectations, without exaggeration, such as: ‘We will do our best to take care of you,’ or: ‘I have seen this treatment work for people like you,’ this is a very strong signal that we should do more of it,” he said.