Psychological changes in young people with anorexia nervosa during an inpatient treatment: exploration of optimal length of stay predictors.

OBJECTIVE: The current study aimed to monitor psychological changes in young people (YP) with anorexia nervosa (AN) during a specialist inpatient treatment in order to explore possible predictors of an optimal length of stay. Outcome measures were analysed to determine if significant changes occur earlier or later on during the treatment. METHODS: Eating Disorder Examination Questionnaire (EDE-Q), Children's Depression Inventory (CDI), State-Trait Anxiety Inventory (STAI) and Compulsive Exercise Test (CET) measures administered to YP (n = 42) at three time points-admission, 85% ideal body weight (IBW) and discharge-were analysed using linear mixed effects model and regression analysis to determine change between the time points and possible predictors in length of stay. RESULTS: Significant improvements occurred between admission and the mid time point of 85% IBW in the eating disorder (ED) symptomology outcome measures of EDE­Q (mean difference [MD] = 1.066 ± 0.259) and CET (MD = 1.743 ± 0.627). A significant improvement occurred in the CDI (MD = 7.714  ± 2.343), and STAI (MD = 5.292 ± 2.121) measures between admission and discharge. CONCLUSIONS: Psychological changes occur at different stages of treatment. Although it was difficult to determine what factors may predict the length of stay from the variables explored, it was observed that a lower weight at admission impacted negatively on the improvement of ED and anxiety symptoms, which may lead to stay in treatment for longer. Also, higher levels of compulsive exercise and depression were associated to worse outcomes. LEVEL IV: Evidence obtained from multiple time series with or without the intervention, such as case studies. Dramatic results in uncontrolled trials might also be regarded as this type of evidence.