Dua (1989) constructed the Thoughts and Real-Life Experiences Scale (THARL) to assess the degree of positive and negative affect experienced by people as a result of their thoughts and day-to-day experiences. This monograph reports on a number of studies designed to investigate the relationship between negative and positive affect caused by thoughts and day-to-day experiences and psychological health, psychological problems, and physical health. Results showed that a preponderance of self-reported negative affect was related to higher levels of stress, depression, poor psychological well-being, poor psychological health, lower self-esteem and poor self-reported retrospective physical health. A preponderance of negative affect was associated with only one of the two measures of prospective physical health, namely, the number of visits to doctors for medical problems over a period of 4 weeks. Positive affect was not associated with either self-esteem or physical health. Assertiveness and Type A/B behaviors were not associated with either negative or positive affect. Also, of the two measures of negative affect, that caused by thoughts seemed to be a better predictor of health, well-being, and psychological problems than that caused by day-to-day experiences.