Applying Autonomous and Controlled Motivation Concepts to the Study of Therapy Outcomes in the Eating-Disorders
General Material Designation
[Thesis]
First Statement of Responsibility
Sansfaçon, Jeanne
Subsequent Statement of Responsibility
Steiger, Howard
.PUBLICATION, DISTRIBUTION, ETC
Name of Publisher, Distributor, etc.
McGill University (Canada)
Date of Publication, Distribution, etc.
2019
PHYSICAL DESCRIPTION
Specific Material Designation and Extent of Item
130
DISSERTATION (THESIS) NOTE
Dissertation or thesis details and type of degree
M.S.
Body granting the degree
McGill University (Canada)
Text preceding or following the note
2019
SUMMARY OR ABSTRACT
Text of Note
Objectives: We sought to better understand the predictive effects of autonomous and controlled motivation on treatment outcomes in people with eating disorders. Towards this goal, we first aimed to validate the Autonomous and Controlled Motivation for Treatment Questionnaire (ACMTQ) - an instrument used in previous research to measure motivation for treatment - for use in a population of women with an eating disorder. We then applied the ACMTQ in an investigation of predictive effects of pre-treatment motivation on therapy outcomes in adults who were undergoing treatment for an eating disorder. Finally, we designed a protocol for a meta-analysis on the predictive effects of pre-treatment motivation on post-treatment outcomes in people undergoing therapy for an eating disorder. Methods: We conducted three studies. In the first study, we validated the ACMTQ in a sample of 463 English- or French-speaking women with an eating disorder. We assessed factor structure, internal reliability, test-retest reliability, as well as convergent, divergent and incremental predictive validity. In the second study, we evaluated the prognostic value of the ACMTQ in 770 adults engaged in an outpatient treatment for an eating disorder. The change in the Eating Disorder Examination Questionnaire total score and the rate of dropout throughout treatment served as outcome measures. Relationships were examined with growth curve modelling and logistic regression analyses. In the third study, we developed a protocol for a meta-analysis of longitudinal studies reporting on the effects of pre-treatment motivation on changes in several indices of eating-disorder severity (i.e., measures of overall eating-disorder symptomatology, weight, bingeing frequency, vomiting frequency, anxiety/depression, and treatment completion rates) at the end of treatment or at follow-up timepoints. We planned to run separate meta-analyses for each outcome studied and to combine effect sizes with random-effect models. Results: Data obtained from the first study showed acceptable fit to our predetermined two-factor model (i.e., autonomous and controlled; comparative fit index = 0.92, root mean square error of approximation = 0.09, standardized root mean square residual = 0.09). Both factors showed good internal consistency (alphas 0.80 and 0.85) and convergent/divergent validity as well as acceptable test-retest reliability (intraclass correlation coefficients = 0.73 for both domains). Higher autonomous motivation predicted better end-of-treatment symptomatology whereas controlled motivation did not. In the second study, we found that higher scores of autonomous motivation were associated with lower scores at end of treatment on the Eating Disorder Examination Questionnaire (coeff. = -0.15, p < 0.005) and with a lower likelihood of dropping out of treatment (OR = 0.81; 95% CI: 0.68, 0.96). Again, controlled motivation for treatment was not associated with response to treatment. Given that the third study is still in progress, results for the latter study will not be reported in this thesis. However, we do include our protocol. Discussion: Overall, results suggested that autonomous motivation for eating-disorder treatment has some positive prognostic effects in individuals with eating disorders.