The word contemplation essentially means to consider or think about something deeply. In the context of the stages of change model of addiction and behavior change, contemplation specifically refers to the stage at which the person engaging in the addictive behavior beings to think about changing, cutting down, moderating or quitting the addictive behavior.
In the stages of change or transtheoretical model, the contemplation stage is separate from the preparation stage or the action stage, so someone at the contemplation stage is generally more open to receiving information about the possible consequences of their addictive behavior than they are to advice to quit. However, they may be open to learning about different strategies for controlling or quitting the addictive behavior, without committing to a specific approach or even to making a change.
People with addictions may be in the contemplation stages for many years. They may move forward to the preparation stage, or they may move backward to the precontemplation stage. Contemplators typically benefit from non-judgmental information-giving, and motivational rather than confrontational approaches to encouraging change. The contemplation stage concludes with the decision to change the addictive behavior.
Sources:
Hartney, E., Orford, J., Dalton, S., Ferrins-Brown, M., Kerr, C. & Maslin, J. "Untreated Heavy Drinkers: a Qualitative and Quantitative Study of Dependence and Readiness to Change." Addiction Research & Theory, 11:317-337. 2003.
Prochaska, J., Velicer, W., Redding, C., Rossi, J., Goldstein, M., DePue, J., Greene, G., Rossi, S., Sun, X., Fava, J., Laforge, R., Rakowski, W. & Plummer, B. "Stage-based expert systems to guide a population of primary care patients to quit smoking, eat healthier, prevent skin cancer, and receive regular mammograms." Preventive Medicine, 41:406-416. 2005.
Segana, C., Borlanda, R. & Greenwood, K. "Can transtheoretical model measures predict relapse from the action stage of change among ex-smokers who quit after calling a quitline?" Addict Behav. 31:414-428. 2006.
Velicer, W. F., Hughes, S. L., Fava, J. L., Prochaska, J. O. & DiClemente, C. C. "An empirical typology of subjects within stage of change." Addict Behav. 20:299-320. 1995.

