Study participants with the highest levels of optimism accounted for less than half the number of cases of angina, nonfatal and fatal heart attacks during the course of the study when compared to pessimistic participants. During the ten-year span of the study 162 out of 1,306 participants developed CHD. Of those, 34 of the cases were from optimists and 77 from pessimists; the remaining 51 cases were among participants ranked as having an explanatory style that was neither strongly optimistic nor pessimistic.