[MUSIC] In about 2007, Paul Tarini from the Robert Wood Johnson Foundation came to me and said we've been reading what you've done in mental health. And we like that positive psychologies take on mental illness says that mental health isn't just the absence of mental illness. It's a real thing, it's the presence of optimism, positive emotions, strengths, meaning in life. So psychological health is a real phenomenon. Is physical health a real phenomenon? Or is physical health merely the absence of physical illness? And so the Robert Wood Johnson Foundation funded the study of what we now call positive health. And the way this began was to look at positive psychological variables in the longitudinal literature on heart attack and on physical illness generally. Now there are a large number of good longitudinal studies. Longitudinal means, by the way, that you take large groups of people at time one, you'd measure all sorts of things about them, and then you wait with those same people. You measure, you measure, you measure, and then you ask how many died, how many got heart disease, how many got cancer and the like. And there are large literatures of longitudinal studies of disease, particularly heart disease and death. But the problem about these is people only thought about risk factors, not protective factors. So they only measured awful things like divorce, tragedy, unemployment, depression, anxiety. They didn't measure protective factors like, do you have a good marriage? Do you love your work? Are you a happy person? So, the way we began was we took the longitudinal studies that existed. And once in a while, we could find one question that was a positive question like, do you have a good marriage? And reanalyzing the longitudinal studies, we found that indeed if you just took the protective positive factors, scraped them out if you will. Held constant the risk factors that the protect people had protective factors seem to have less heart disease and less death. Indeed, that's where things were through about 2010 but then, the material that I talked about in the last lecture came along, the material from the army. Because what the army does is to keep really good records. And we created the GAT, the General Assessment Tool, to measure things like do you have a good marriage, how happy are you, how much meaning do you have in life? So we now have the entire dataset of the United States Army from 2009 going forward along with things like suicide, homicide, cancer, depression, and heart attack. And so, we will be able to get, and we're starting to get, definitive answers to the mind body questions on now, 1.3 million soldiers with a huge amount of data on them. But in the mean time, several well done studies in which the positive things were measured, have been done. I'll just mention one to you, this is 999 Dutch adults. So they're measured at age 65 and the target is going to be death from heart attack over the next ten years. And everything is measured, blood pressure, cholesterol, obesity, Along with optimism. And so the results of this study ten years down the road, about a third of the 1,000 people have died of a heart attack and the only robust predictor is optimism and pessimism. So partialing out that is holding constant the traditional risk factors like weight and blood pressure, optimistic people have much lower rates of heart attack and death than pessimistic people. And in fact, if you quantify the variable, being in the bottom quartile of pessimists is roughly equivalent to smoking two to three packs of cigarettes a day. So importantly, there are now about 20 studies, which for cardiovascular disease, have shown that pessimism is a risk factor, and optimism is a protective factor. Now, this isn't universal across diseases. So, in very elegant set of experiments Sheldon Cone gives people colds in laboratory. And here's a give people colds, you set up a surgical unit in which people agree to live in it for two weeks. And you squirt into their nose a fixed amount of cold virus. And you ask the question, who gets the cold and who doesn't? And you measure it, not just by do you have a cold, but you weigh the mucus. So you have good quantitative measures of getting a cold. And you measure beforehand variables like optimism, cheerfulness, depression, anxiety. Here optimism doesn't make a difference. But cheerfulness, optimism is about how you see the long term future. Cheerfulness is, do you smile a lot right now? Are you a merry, happy person? So merry, happy, cheerful people fight off colds, optimism makes no difference. So the summary of that literature is for cardiovascular death. Being an optimist or a pessimist really matters. For infectious illness, being a cheerful or a glum person seems to matter. There's a huge controversy in the cancer literature. So, Barbara Ehrenreich, as some of you may know, wrote a book damning me called Bright-Sided, in which she had breast cancer. And Barbara claimed that people making her do pink things was a waste of time and was noxious and the like. And she can't stand these people who tell breast cancer patients to be positive and to be happy. So the question is, does positivity matter in the cancer literature? And the answer is really unknown. And when this first came out, I said something like, positivity, positive psychology matters for marginal diseases. So to summarize the literature on physical health, there are psychological states which put you at risk or protect you from physical illness and from death. So for cardiovascular disease, being a pessimist is a risk factor, being an optimist is a protective factor. For infectious illness, being a merry person is protective, being a glum is probably a risk factor. And for cancer, we just don't know.