COmparison Between Continued Inpatient Treatment Versus Day Patient Treatment in Early Onset Anorexia Nervosa

The objective of the study is to demonstrate the non-inferiority of DH management after a short full-time hospitalisation compared to a prolonged full-time hospitalisation aiming at a healthy weight on the evolution of BMI at 1 year in children aged 8 to 13 years suffering from anorexia nervosa, with severe undernutrition.

The minimum healthy weight is defined by a weight corresponding to the BMI corridor prior to the diagnosis of anorexia nervosa, +/- 1 corridor).

Randomized controlled trial, open-label, single-centre.

Patients will be randomized into one of the two arms of the trial:

• Group 1 (control group): continuation of full-time hospitalisation until reaching the minimum healthy weight, defined as the weight corresponding to the return to the previous BMI corridor (previous BMI +/- 1 BMI corridor, e.g. change from 25th to 10th percentile).
• Group 2 (experimental group): Exit from FTH (full-time hospitalisation ) and relay to DH (day hospitalization ) one day per week until the minimum healthy weight. This treatment combines a one-day medical evaluation by a senior psychiatrist, family sessions (parents group and multi-family therapy session), a therapeutic education group, a cognitive remediation group and a dietary follow-up with therapeutic meals.

Statistical analysis of the data will be carried out with the intention to treat. The BMI at 1 year between groups, as well as its bilateral 95% confidence interval (equivalent to a one-sided 97.5% confidence interval), will be estimated and compared with the predefined margin of non-inferiority (1 BMI point).

Ancillary study : Addition of a qualitative study conducted with parents to evaluate the implementation of a weekly intensive day hospital in the treatment of early-onset anorexia nervosa.

Inclusion criteria

• Anorexia Nervosa according to diagnostic mental disorders(DSM 5) criteria;
• Age at diagnosis 8 to 13 years inclusive;
• Indication for full-time hospitalisation according to supreme health authority (HAS 2010) criteria, see appendix;
• First hospitalization in the Eating Disorders (ED) unit of the Child and Adolescent Psychiatry Department at Robert Debré Hospital.
• Informed consent of the holder(s) of parental authority
• Patient affiliated to a social security

Exclusion criteria

• Other early onset eating disorders (ARFID to DSM 5 criteria) ;
• Underlying unbalanced somatic disease (especially gastroenterological);
• Psychiatric indication for continued hospitalisation (in particular significant suicidal risk according to the psychiatric criteria for full-time hospitalisation for anorexia nervosa of the HAS, 2010, cf. appendix)
• Environmental indication for continued full-time hospitalization according to the HAS environmental criteria for full-time hospitalization for anorexia nervosa, 2010, cf. appendix) ;
• History of full-time hospitalisation in our ED unit.