Comorbid mental disorders during long-term course in a nationwide cohort of patients with anorexia nervosa

Int J Eat Disord. 2021 Sep;54(9):1608-1618. doi: 10.1002/eat.23570. Epub 2021 Jun 18.


Objective: Comorbid mental disorders in anorexia nervosa during long-term course require detailed studies.

Method: This matched cohort study was based on nationwide Danish register data of all patients born 1961-2008 with a first-time ICD-10 diagnosis of anorexia nervosa (AN) between 1994 and 2018 at age 8-32 and matched controls taken from all individuals without an eating disorder (ED). For nine categories of non-eating mental disorders, time from date of first AN-diagnosis (inclusion date) to time of first diagnosis, accounting for censoring, was studied by use of time-stratified Cox models.

Results: A total of 9,985 patients with AN (93.5% females) and 49,351 matched controls were followed for a median (IQR) of 9.0 (4.4-15.7) years. For patients, there was about 25% and 55% risk of receiving any non-ED disorder during the first 2 years and two decades after inclusion, respectively. A hazard ratio (HR) of seven for any non-ED was found for the first 12 months after inclusion, a ratio that reduced to two at five or more years after inclusion. During the first years, large HRs ranging in 6-9 were found for affective, autism spectrum, personality, and obsessive-compulsive disorders with the latter displaying the highest continuous increased risk. The HR at 12 months after inclusion was highest for any non-ED disorder and affective disorders in patients aged 8-13 at diagnosis.

Discussion: Comorbid mental disorders in AN are most frequently diagnosed in the first years after diagnosis of AN and on longer terms imply a double immediate risk.

Keywords: anorexia nervosa; comorbidity; epidemiology; matched cohort design; register data.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Anorexia Nervosa* / diagnosis
  • Anorexia Nervosa* / epidemiology
  • Child
  • Cohort Studies
  • Comorbidity
  • Feeding and Eating Disorders*
  • Female
  • Humans
  • Male
  • Mental Disorders* / diagnosis
  • Mental Disorders* / epidemiology
  • Obsessive-Compulsive Disorder* / epidemiology
  • Personality Disorders
  • Young Adult