Motivational change in an inpatient anorexia nervosa population and implications for treatment

The relationship between motivation and recovery in anorexia nervosa has received increased attention in the research literature although few controlled investigations of increasing motivation in this population exist. Three questions were therefore examined in an inpatient anorexia nervosa population: (i) does baseline motivation predict change in eating pathology; (ii) does change in motivation predict change in eating pathology; and (iii) can we increase motivation to recover in this group?

Inpatients (n=47) in a specialist weight disorder unit with a mean age of 21.85 years (SD=5.37) were randomly allocated to receive four sessions of motivational interviewing with a novice therapist in addition to treatment as usual (n=22) or treatment as usual alone (n=25). Assessment of eating pathology and motivation to recover was conducted on three occasions: at admission (baseline), and at 2- and 6 week follow up. Eating pathology was assessed using the Eating Disorder Examination and self-reported motivation was assessed using the Anorexia Nervosa Stages of Change Questionnaire and six Likert scales.

Higher baseline motivation across five of the seven measures predicted significant decreases in eating pathology, and increased Anorexia Nervosa Stages of Change Questionnaire scores between baseline and 2 week follow up predicted significant improvement in eating pathology between baseline and 6 week follow up. Significantly more patients were lost to follow up from the treatment as usual compared to the motivational interviewing group. More patients in the motivational interviewing condition moved from low readiness to change at baseline to high readiness to change at 2 and 6 week follow up.

Motivation is an important predictor of change in anorexia nervosa and preliminary evidence is provided that motivation can be improved in this population. Further investigations, however, of ways of improving motivation in this population need to be conducted, along with the impact of motivational changes on treatment outcome.