Theories of motivation in addiction treatment: Testing the relationship of the transtheoretical model of change and self-determination theory

This study explored the relationship between 2 theories of motivation: self-determination theory (SDT) and the transtheoretical model of change (TTM), and sought to determine whether the source of motivation described by SDT would predict TTM's stage of change. SDT was operationalized as the level of internal or external motivation for treatment, and TTM was operationalized as 3 stages of change: precontemplation, contemplation, and action. Our data came from the Drug Abuse Treatment Outcome Study published in 2004. A multinomial logistic regression analysis indicated that there was a significant relationship between source of motivation and stage of change at intake. Controlling for severity, treatment history, legal status, and primary substance use, persons entering treatment with higher levels of internal motivation were more likely to be in the action stage than the precontemplation stage. Higher levels of internal motivation also predicted a greater likelihood of being in the contemplation rather than the precontemplation stage.