This observational study compares parental age and birth order in patients diagnosed with anorexia nervosa and bulimia nervosa.

Study participants are recruited (300 patients for each entity). Healthy subjects without evidence of an eating disorder serve as a control group. Psychometric assessment will include data on pathological eating behavior and general psychological and interpersonal problems.

Outcome measures The SCL-90-R questionnaire is a self-report inventory for adolescents and adults that assesses a wide range of psychological problems and symptoms of psychopathology. The questionnaire consists of 90 items, each of which contributes to one of nine primary symptom dimensions.

The short form of the Inventory of Interpersonal Problems (IIP-C) is used to measure interpersonal problems. This self-report questionnaire contains 64 items assigned to eight subscales.

Eligible candidates are stratified as cases or matched controls as follows:

1. Cases are eligible patients diagnosed with anorexia nervosa or bulimia nervosa (n=300 for each entity) at the time of study inclusion.
2. Controls (100) are healthy subjects of a similar age distribution and from the same study site without the diagnosis of an eating disorder.

Inclusion criteria:

- Age > 12 and < 59 years (adolescents and adults).

Exclusion criteria:

• Diagnosed with a malignant disease
• Not fluent in the German language
• Severe mental disorder

Inclusion Criteria:

- Age > 12 and < 59 years (adolescents and adults) with either anorexia nervosa or bulimia nervosa.

Exclusion Criteria:

• Diagnosed with a malignant disease
• Not fluent in the German language
• Severe mental disorder

Study participants with diagnosed anorexia nervosa or bulimia nervosa according to ICD-10 criteria