What is anorexia nervosa?
Anorexia nervosa is an eating disorder caused by a biological disorder of the brain that leads to a distorted body image and under-eating to maintain an unhealthy low weight.
People with anorexia nervosa have an overpowering fear of being overweight and an extreme desire to be thin. They may also have a distorted body image which causes them to see themselves as overweight when they are not. This can cause them to engage in behaviours that will result in weight loss such as dieting or restricting their food intake, over-exercising, and/or using medication to control their appetite.
Anorexia nervosa can affect anyone regardless of body shape, size, weight, age, gender, ethnicity and socioeconomic background. Anorexia nervosa is not a choice; it is a serious and life-threatening biologically-influenced illness.
What causes anorexia nervosa?
The exact causes of anorexia nervosa are unknown. Generally, anorexia nervosa results from a mix of social factors, stressful life events, and genetics.
Social factors
Taking part in activities that emphasize thinness, such as ballet, gymnastics and modelling, may be a factor in developing anorexia nervosa. Other social factors include pressure to fit in with peers and the media's emphasis on a very narrow range of ideal body types such as being thin or very muscular.
Stressful life events
A person might develop anorexia nervosa if they do not feel in control over their own life, especially during or after a stressful event. They will try to control their calorie intake to exert extreme control over their eating and their weight. This is done to regain perceived control when other aspects of their lives feel uncontrollable.
Genetics
Having a relative who has been diagnosed with an eating disorder may be a risk factor for developing anorexia nervosa. If anorexia nervosa is present, it is also common for there to be a family history of anxiety disorders.
Who is affected by anorexia nervosa?
Anorexia nervosa mainly affects teenage girls aged 13 to 15 years, but it can emerge at any age. In recent years, larger numbers of boys and younger children are being seen with anorexia nervosa and other eating disorders.
At SickKids
SickKids has an eating disorder program that treats children and teens who are struggling with symptoms of anorexia nervosa, bulimia nervosa and avoidant restrictive food intake disorder. For more information on our program visit: www.sickkids.ca/adolescentmedicine/eating-disorders-program
Further information
For more information on anorexia nervosa, please see the following pages:
Anorexia nervosa: Signs and symptoms
Anorexia nervosa: Medical complications
Anorexia nervosa: Treatment options
Anorexia nervosa: How to help your child at home
Please visit our teen mental health hub for teen-specific resources on
anorexia nervosa.
Resources
NEDIC – National Eating Disorder Information Centre (Canada)
NEDA – National Eating Disorder Association (United States)
American Academy of Pediatrics – Eating Disorders in Children
BEAT – Beating Eating Disorders (United Kingdom)
Kelty Eating Disorders (Kelty Mental Health Resource Centre, BC Children's Hospital)
Children's Hospital of Eastern Ontario – Eating Disorders
ANAD – National Association of Anorexia Nervosa and Associated Disorders (United States)
Virtual care services for children:
Boomerang Health was opened by SickKids to provide communities in Ontario with greater access to community-based services for children and adolescents. For more information on virtual care services in Ontario to support eating disorders, visit Boomerang Health powered by SickKids.