How weird would it be if you could think yourself to poor health? Oh wait; that's actually a thing. It's called the 'nocebo effect.'
"We have long known that expectations of a malady can be as dangerous as a virus," writes David Robson for the BBC. "Vomiting, dizziness, headaches, and even death, could be triggered through belief alone."
That's right – even death.
Records show that, in the 18th Century, some medical students in Vienna decided to pick on a well-hated assistant. They blindfolded the man and told him he would be decapitated. When the students dropped a wet towel on his head, he was so convinced it was a knife that he died on the spot.
Yup, that is a thing that actually happened.
But the nocebo effect is not always triggered by that sort of dramatic trauma. No, it's usually much more subtle.
Let's look at a few types of negative thought and explore their health implications.
Cynicism is a general distrust of other human beings. It's an increasingly common worldview – and that's quite unfortunate, since researchers have linked cynicism to an increased dementia risk. These findings held true even after researchers accounted for other risk factors like age, gender and smoking habits.
Dementia is just one pitfall of cynicism. Back in 2009, researchers linked it to an increased heart disease risk in women.
The key word there is 'chronic.' Anger is a totally normal emotion; it's only problematic when it becomes a "more permanent disposition or habitual outlook on the world," as Dr. Emiliana Simon-Thomas puts it.
In other words, if you walk around getting upset at everything, you're gonna have a bad time. How bad? How's a 19% higher risk of cardiovascular disease and a 70% higher risk of death by cancer sound?
Negative Thought Pattern #1 – Cynicism

Negative Thought Pattern #2 – Hostility
If you want to have a stroke, be a jerk. That's advice we can deduce from a 2014 study. In the study, individuals who ranked higher on hostility and unfriendliness tests displayed an increased stroke risk. Researchers could not figure out exactly why this was the case. They've got some theories, though, which we'll explore after point #3.Negative Thought Pattern #3 – Chronic Anger
