title: Self-Determination Theory and the Theory of Planned Behaviour Applied to Substance Abuse Treatment in a Therapeutic Community Setting
Creators: name: Klag, Stefanie
Publisher: name: Griffith University
Year: 2006
Subjects: subject: Self-determination theory
subject: substance abuse treatment
subject: drug abuse
subject: alcohol abuse
subject: motivational theory
subject: Theory of Planned Behavior

description: In the 21st century drug and alcohol abuse presents one of the most serious problems worldwide. Of particular concern is the strong relationship between drug use and crime. While law enforcement strategies, including incarceration, have been revealed to contribute little to break the vicious cycle of drug use and crime, substance abuse treatment has been shown to represent an effective form of intervention. Substantial research on the effectiveness of drug treatment has demonstrated the importance of motivation in predicting treatment retention and success. However, substance users are frequently coerced into therapy by external sources, including the criminal justice system, therefore, typically exhibiting little motivation to enter and remain in treatment long enough to overcome their substance addiction. Although past research investigating the effects of treatment-entry coercion indicates positive treatment results, the vast majority of these studies are seriously impeded by extensive conceptual and methodological problems, questioning the postulated value of coercion in substance abuse treatment. Following the call for a shift in the methodological focus of future studies made by some researchers, the author of the present study tested three models that were based on well-established theories. The first model was based on Self Determination Theory (SDT), a motivational theory, while the second model was based on the Theory of Planned Behaviour (TPB), an expectancy-value theory. The third model consisted of a combination of the two theories, which was argued to provide a more complete and comprehensive model than each theory on its own. The testing of the models allowed the exploration of the dynamic interplay and relationships between a number of variables including perceptions of coercion, motivation, perceived autonomy support, and behavioural intentions in an effort to explain and predict retention and treatment outcomes amongst drug and alcohol abusers. The study was conducted in two phases. Phase 1 involved the development of a 29-item instrument called the Perceived Coercion Questionnaire, which was designed to assess participants' perceptions of coercion to enter drug and alcohol treatment originating from six different sources. The scale was shown to be a valid and reliable measure of the coercion construct. Phase 2 involved the testing of the three models longitudinally by using a sample of 350 substance abusers from six therapeutic communities across Australia. Participants were asked to complete a battery of standardised measures within the first two weeks of treatment admission (Time 1), two months into treatment (Time 2), and at completion of the treatment program (Time 3). The models were tested cross-sectionally and longitudinally employing hierarchical multiple regression analysis. In addition, change scores were calculated to test whether changes in predictor variables would predict outcomes and changes in outcomes cross-sectionally and longitudinally. Analyses of Time 1 and Time 2 cross-sectional data revealed that the SDT model, compared to the TPB and the combined model, provided a better and more parsimonious account of the factors that influence outcomes in therapeutic community treatment. Given the complexity of the study, it was decided to resume the analysis by focusing on the investigation of the SDT model alone. To highlight some of the most important findings, results demonstrated that motivation was a key factor in the treatment and rehabilitation of substance users. As anticipated, intrinsic motivation was consistently predictive of retention and more positive treatment outcomes, while external motivation and amotivation were associated with more negative outcomes. Results also revealed that clients who entered treatment as the result of a legal mandate experienced substantially higher levels of legal coercion compared to clients who entered treatment voluntarily. Legal coercion, in turn, was found to exert a negative impact on substance users' motivation for treatment, thereby indirectly resulting in more negative treatment outcomes. In contrast, self coercion (i.e., feelings of pain and suffering) and health-related pressures seemed to facilitate the development of a more intrinsic motivational attitude towards treatment. Besides, perceptions of competence and control in relation to the therapeutic regime emerged as consistent and important predictors of motivation and treatment outcomes. Finally, findings suggested that treatment staff who employed more autonomous and non-coercive strategies that guided substance users through the change process directly influenced individuals' treatment motivation and thereby facilitated more positive treatment outcomes. In sum, findings provided support for the usefulness of the SDT model in predicting dropout as well as processes and outcomes in therapeutic community drug and alcohol treatment. Implications for residential substance abuse treatment were discussed, as well as the strengths and limitations of the study. The discussion concludes with implications for practice and suggestions for future research.