Transtheoretical principles and processes for quitting smoking: a 24-month comparison of a representative sample of quitters, relapsers, and non-quitters.

This longitudinal study compared 14 principles and processes of change applied by successful quitters, relapsers and non-quitters over 24 months in a representative sample of 4144 smokers in intervention and control groups. The successful quitters showed a decrease in the use of experiential processes (cognitive, affective and effective) and an increase in behavioral processes (e.g.