The Eysenck Personality Inventory measures the traits of stability versus neuroticism (N) and introversion versus extroversion (E).

Scale N gives the therapist a general idea of how an individual acts towards stressors in life and the probability that they will "crack" under stress. The higher the N score, the more likely the person will be able to control their emotions. An extrovert is a person who is not shy and is outgoing. The greater the E score, the more apt the person is to being content, social and positive. These individuals are very active, have high energy levels and need a lot of excitement in their lives.