breast cancer patients saw the experience of serious illness and subsequent recovery as transformative; they didn’t just go back to being who they were. They became different, and two-thirds of them said they’d changed for the better. But this sense of well-being came at a price. Taylor dryly noted, “From many of their accounts there emerged a mildly disturbing disregard for the truth.” The women emerged with a greater sense of control over their disease or their recovery than was actually the case. The typical patient consistently overestimated her likely survival compared to the known statistics and her own medical status. Interviewing the oncologists and psychotherapists who cared for these patients, the researchers found that their unrealistically optimistic attitudes correlated with better psychological adjustment. That is, the psychologically healthier patients were the most unrealistic. Taylor had discovered “positive illusion”—the opposite of depressive realism, a kind of healthy illusion found not just in a trivial button-pushing test, but in life-threatening illness.

S. Nassir Ghaemi, A first-rate madness: uncovering the links between leadership and mental illness, New York, NY, 2012, p. 60