Before I dive into the scientific evidence about whether optimism and pessimism impact health outcomes, let me tell you a short story. When I was a young medical student, I had the opportunity to trail Professor John Englebert (“Bert”) Dunphy on his evening rounds. He was at that time the widely admired and beloved Chairman of the Department of Surgery at the University of California San Francisco.
The good doctor always made a point of visiting his patients the evening before their scheduled surgery. During that visit, he would engage them in a conversation about their upcoming surgery. He would also ask them about their families and their outlook on life in general.
Afterward, he would go to the nurses’ station and strike off the next morning’s list of patients those that were pessimistic about their odds of a successful procedure. I have always remembered what he told me about why he did this:
“In my experience, he said, their odds of surviving a difficult procedure or post-op period are pretty slim.”
I was awe-struck, though my feelings were mixed with a healthy dose of skepticism. In those days, surgeons justified just about everything they did with the phrase, “in my experience.”
Pessimism and poor health outcomes health
Sometime later, an article by Pauline Chen, MD caught my attention. In it, she describes an episode from her medical practice. Her patient, a diabetic, had been hospitalized for a toe infection that should have responded to a simple course of IV antibiotics. But, in this case, it did not.
Instead, the patient required a series of amputations—each one higher up the foot—in an attempt to stem the infection. He began to lose weight and eventually required nutritional support. Then, one day, he died.
Before he died, Dr. Chen asked a consulting psychiatrist if her patient was depressed? “He’s not,” the consulting psychiatrist told her, “it’s just the way he is.” In other words, he was a pessimist by nature.
Now, these are interesting anecdotes, but you might be thinking, is there actually any scientific evidence that optimism or pessimism can impact health outcomes?
The scientific evidence that optimism and pessimism impact health
In fact, there is real scientific evidence that an optimistic disposition leads to better health. The converse is true for pessimism. Here are but a few findings, out of dozens of articles published on the subject over the last 20 to 25 years:
- Optimists are twice as likely to be in ideal cardiovascular health, according to a study led by Rosalba Hernandez, a professor of social work at the University of Illinois.
- Optimistic individuals recover more quickly following cardiac-related events, such as coronary artery bypass surgery and myocardial infarction. They have a more rapid return to a normal lifestyle and a better-reported quality of life.
- Edna Maria Vissoci Reiche and colleagues have found that pessimists are prone to higher levels of stress hormones, lowered immune response, and increased levels of cancer.
- Optimism also appears to be associated with lower levels of distress, slower disease progression, and improved survival rates in patients with HIV.
More by this author: The Unfortunate Consequences of Disbelieving in Free Will
Optimism and cause-specific mortality
A more recent study by Kim et al. in the American Journal of Epidemiology examined the association between optimism and cause-specific mortality. The strength of this study is that it was prospective. It is also statistically well-powered using data from 70,021 participants in the Nurses Health Study.
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The researchers measured the participants’ optimism using a standardized instrument calls the Life Orientation Test-Revised. They then divided the study population into four groups based on their degree of optimism, from lowest to highest.
Related content: Positive Psychiatry: What is It and Why We Need It
The least optimistic group was assigned a hazard ratio (HR) of 1.0. It served as the comparison group for the other more optimistic groups. An HR of less than 1 indicates that a group is less likely to have “an event” compared to the least optimistic group. In this study, the events were a type of medical condition, such as heart disease or stroke.
Here are the HRs they found when comparing the most optimistic quartile to the least for mortality from different conditions:
- heart disease = 0.62
- stroke = 0.61
- respiratory disease = 0.63
- infection = 0.48
- all cancers = 0.84
This suggests a strong association between high optimism and lower mortality from these different diseases. The researchers constructed various models to test whether the association was due to confounding variables, such as sociodemographic factors, depression, and prior illness. Although in some cases the strength of the association was reduced, it was not eliminated.
Optimism and longevity
The good news is that there are numerous studies showing that optimists live longer. Here are a sampling of studies from a variety of well-respected researchers and institutions:
Giltay’s Delft study
In another study, a team led by Erik Giltay, MD, Ph.D., of Psychiatric Center GGZ Delfland, Delft, the Netherlands, interviewed ~1,000 men and women (ages 65-85) about health, self-respect, morale, optimism, contacts, and relationships.
They included two key questions regarding optimism:
- Do you often feel like life is full of promise
- Do you still have many goals to strive for?
Answering yes to these questions revealed a sense of optimism.
During the nine-year follow-up period, Dr. Giltay and his colleagues found that those participants who reported higher levels of optimism were 55% less likely to die from any cause and 23% less likely to die from a heart-related illness as compared to the pessimistic group.
Hilary Tindle of the University of Pittsburgh
Another study, led by Dr. Hilary Tindle of the University of Pittsburgh, found similar results. The researchers used data from the Women’s Health Initiative, an ongoing government study of more than 100,000 women over age 50 that began in 1994. Participants completed a standard questionnaire that measured optimistic tendencies based on their responses to statements like, “In uncertain times, I expect the worst.”
Their results showed that eight years into the study, women who scored the highest in optimism were 14% more likely to be alive than those with the lowest, most pessimistic scores. The pessimists were more likely to have died from any cause, including heart disease and cancer.
Drilling down, they found that pessimistic black women were 33% more likely to have died after eight years than optimistic black women, whereas white pessimists were only 13% more likely to have died than their optimistic counterparts.
As Dr. Tindle notes, pessimistic women tended to agree with statements like, “I’ve often had to take orders from someone who didn’t know as much as I did” or “It’s safest to trust nobody.” She accounted for confounding factors such as income, education, health behaviors like controlling blood pressure, degree of physical activity, drinking, and smoking and still found that optimists had a decreased risk of death compared to pessimists.
It is noteworthy that the title of Tindle’s article described above is revealing: “Optimism, cynical hostility, and incident coronary heart disease and mortality in the Women’s Health Initiative.” In her study, counter to optimism is not just pessimism, rather, it is cynical hostility.
In other words, the class of “non-optimists” is not limited to the woe-is-me individual. It includes people who may feel optimistic about their own prospects, but are cynical and hostile to others.
So, the underlying factors that govern our health and longevity are not merely cheerfulness versus moroseness, they are also
- positive versus negative attitudes,
- compassion versus hostility,
- love versus hate.
Dr. Tindle expands on this profound, and uplifting theme in her aptly named book: “Up: How Positive Outlook Can Transform Our Health and Aging. I highly recommend it.
Eric Kim’s groups at Rockefeller University
A recent study from the Rockefeller University, published in 2019, looked at the effect of optimism on longevity. According to the authors, their results “suggest that optimism is specifically related to 11 to 15% longer life span, on average.”
They also found optimistic people have greater odds of achieving what they call “exceptional longevity” – living to the age of 85 or beyond.
These relationships were independent of socioeconomic status, health conditions, depression, social integration, and health behaviors (e.g., smoking, diet, and alcohol use).
Limitations of the studies
It is important to point out that these studies are all association studies. They have not been designed to prove that it was optimism that caused the better outcomes. It could be that optimistic people are more likely to have a healthier lifestyle, including eating better diets, avoidance of drugs or excessive alcohol, and exercising more. Determining cause and effect requires a randomized, controlled study design.
The bottom line
There is a substantial body of literature that strongly suggests an association between one’s outlook on life and one’s health outcomes, including longevity. Although, as we always say in medicine, definitive proof requires that we do more better studies.
That being said, there are no downsides to learning to be more optimistic. I suggest you try it – you just might like the results.
First published on 03/23/15. Reviewed and updated by the author on 07/07/2017 and again on 5/9/2020.
Dov Michaeli, MD, PhD
Dov Michaeli, M.D., Ph.D. (now retired) was a professor and basic science researcher at the University of California San Francisco. In addition to his clinical and research responsibilities, he also taught biochemistry to first-year medical students for many years.
During this time he was also the Editor of Lange Medical Publications, a company that developed and produced medical texts that were widely used by health professionals around the world.
He loves to write about the brain and human behavior as well as translate knowledge and complicated basic science concepts into entertainment for the rest of us.
He eventually left academia to enter the world of biotech. He served as the Chief Medical Officer of biotech companies, including Aphton Corporation. He also founded and served as the CEO of Madah Medica, an early-stage biotech company that developed products to improve post-surgical pain control.
Now that he is retired, he enjoys working out for two hours every day. He also follows the stock market, travels the world, and, of course, writes for TDWI.