Understanding How People Change is First Step in Changing Unhealthy Behavior

Stages-of-change research has been used to develop dozens of behavior change programs, including HIV prevention, to help people live longer, healthier lives.


Many people are familiar with the five stages of grief, but did you know there are five stages of change? In a study involving 872 people who were trying to change their smoking habits, psychologists Carlo DiClemente, PhD, and James O. Prochaska, PhD, identified five stages of change, which became a cornerstone of a Transtheoretical Model of Change. These stages include precontemplation, contemplation, preparation, action, and maintenance. Once in the contemplation stage, people were most likely to respond to feedback and education as sources of information about smoking. Preparation stage folks were committed to changing and seeking a plan of action. Those in the action and maintenance stages were actively changing their smoking behaviors and environments and found that social reinforcers were important. Those who had relapsed were found to cycle back into earlier stages as they geared up to quit again.


Based on this research, we have a better understanding of not only how people change, but also how to help people in their efforts to change. This understanding of the process of change has been used to develop dozens of behavior change programs and interventions that focus on the decision making of the individual.

Practical Application

The stages-of-change model has led to the development of a community-level HIV intervention that has been shown to reduce behaviors that put people at greater risk for HIV. The Centers for Disease Control implemented the AIDS Community Demonstration Projects with at-risk populations in Dallas, Denver, Long Beach, New York, and Seattle. In an effort to decrease HIV risk, the project promoted consistent condom use and bleach use for hypodermic needles. The project used the stages-of-change model to design interventions that were appropriate to individuals' stage of change. It was hoped that the interventions would move people at least one stage of change in condom use. (e.g. from no intention to use condoms to at least a short or long-term intention to use condoms). At the community level, results showed movement toward consistent condom use as well as increased condom carrying. At the individual level, respondents recently exposed to the intervention were more likely to carry condoms and have higher stages-of-change scores for condom and bleach use.

In addition, The Cancer Prevention Research Center at the University of Rhode Island and other investigators across the country have developed intervention material based on the Transtheoretical Model of Change. The interventions include over a dozen behavioral topics ranging from seatbelt use to increasing exercise to adopting a low-fat diet. Additional information on these applications can be found on the web sites listed below under Additional Sources.

Cited Research and Additional Research Support

CDC AIDS Community Demonstration Projects Research Group (1999). Community-level HIV intervention in 5 cities: Final outcome data from the CDC AIDS Community Demonstration Projects. American Journal of Public Health, Vol. 89, pp. 336-345.

DiClemente, C. C. & Prochaska, J. O. (1982). Self-change and therapy change of smoking behavior: A comparison of processes of change in cessation and maintenance. Addictive Behaviors, Vol. 7, pp. 133-142.

DiClemente, C. C. (2003). Addiction and Change: How addictions develop and addicted people recover. New York: Guilford Press.

Marcus, B. H., Banspach, S. W., Lefebvre, R. C., Rossi, J. S., Carleton, R. A., & Abrams, D. B. (1992). Using the stages of change model to increase the adoption of physical activity among community participants. American Journal of Health Promotion, Vol. 6, pp. 424-429.

Nigg, C. R., Burbank, P. M., Padula, C., Dufresne, R., Rossi, J. S., Velicer, W. F., Laforge, R. G., & Prochaska, J. O. (1999). Stages of change across ten health risk behaviors for older adults. The Gerontologist, Vol. 39, pp. 473-482.

Prochaska, J. O. & DiClemente, C. C. (1983). Stages and processes of self-change of smoking: Toward an integrative model of change. Journal of Consulting and Clinical Psychology, Vol. 51, pp. 390-395.

Prochaska, J. O., DiClemente, C. C., & Norcross, J. C. (1992). In search of how people change: Applications to addictive behaviors. American Psychologist, Vol. 47, pp. 1102-1114.

American Psychological Association, December 3, 2003