A long-running study found that people who scored higher on a pessimism scale during college had a higher death rate over the next 40 years than those who scored lower. The finding is interesting for mind-body health, but it does not prove that telling yourself to think positively will make you live longer.
What researchers measured
In the mid-1960s, 7,007 students entering the University of North Carolina completed a personality questionnaire. Researchers had usable optimism-pessimism scores and later mortality records for 6,958 of them. Over about 40 years, 476 participants died. Compared with the lowest third of the pessimism scale, the highest third had an estimated 42% higher rate of death after adjustment for sex. The original study is Prediction of all-cause mortality by optimism-pessimism scores.
That 42% is a relative difference between groups, not a person's chance of dying because of a thought. The study did not randomly assign an optimism practice and follow its effects. Personality scores may be connected to other factors, such as mental health, smoking, relationships, or circumstances that change over decades. The analysis reported in the abstract adjusted for sex, leaving many possible explanations open.
Can a positive-thinking practice change health?
This particular paper cannot answer that question. A practice such as mindfulness, journaling, or time with supportive people might help someone cope and feel better, even without proof that it changes lifespan. A later cohort study separated optimism and pessimism scores and found that pessimism predicted mortality while optimism itself was not clearly protective (Pessimism and optimism mortality cohort study). That is one reason not to turn the older association into an instruction to be cheerful.
Health problems are not a personal failure to think positively. People dealing with pain, grief, or depression deserve support rather than blame. The practical message is to use mind-body practices if they help daily life, while understanding that the 40-year study observed an association and did not test a treatment.
