Type A and Type B personality theory

The Type A and Type B personality theory associates two contrasting personality types with different incidence of coronary heart disease. According to the theory, people who are habitually competitive and impatient are labeled Type A, while more relaxed people are labeled Type B. While it was widely discussed in early health psychology research, the theory is now mostly considered historical and is not commonly used in modern personality psychology.

Source: Wikipedia — Type A and Type B personality theory (CC BY-SA 4.0)