By Sally Robertson, BSc
Eating disorders, such as anorexia nervosa, bulimia and binge eating, are characterised by an unusual attitude towards food that may cause an individual to alter their eating habits and eating behaviour.
No single cause for eating disorders has been established. Although a preoccupation with body weight and body shape seem to be central to all eating disorders, research has so far shown that eating disorders are associated with (but not caused by) many different factors, which may be genetic, cultural, social, behavioural, psychological or biological.
Therefore, any “cause” of an eating disorder may be multifactorial and complex.
Risk Factors for Eating Disorders
Eating disorders can affect individuals from any race, age or socioeconomic class. Risk factors that increase the likelihood of developing an eating disorder include:
Research suggests that genetic factors may increase the likelihood of an individual developing an eating disorder. Individuals with a first-degree relative who has a history of an eating disorder are more likely than individuals without such a relative, to themselves develop an eating disorder. In addition, researchers have identified specific genes that influence hormones such as leptin and ghrelin. Experts believe that as well as regulating feeding, these hormones may influence the personality traits and behaviours that are associated with anorexia and bulimia.
Influences at Home or at School
Existing research into the role of family in triggering an eating disorder is largely cross-sectional, retrospective and unsubstantiated. However, it has been suggested that parents’ behaviours may influence their child’s eating habits. For example, mothers who diet or worry excessively about their weight may trigger their child to develop an abnormal attitude towards food, as may a father or sibling who teases an individual about their weight or shape.
Similarly, comments made by classmates in the school environment can influence a child’s attitude to eating habits and a parent or teacher’s high expectations of a child’s performance at school may also help lay the foundations for an eating disorder.
Personality and Character
People with eating disorders tend to share similar personality and behavioural traits such as low self-esteem, perfectionism, approval seeking, dependency, and problems with self-direction.
In addition, specific personality disorders can increase the risk for developing eating disorders, these include:
Avoidant Personality Disorder
People with this condition are typically perfectionist, emotionally and sexually inhibited, nonrebellious and terrified of being criticized or humiliated.
Obsessive-Compulsive Personality Disorder
Individuals with this disorder may be perfectionist, morally rigid, or overly concerned with rules and order.
Borderline Personality Disorder
This disorder is associated with self-destructive and impulsive behaviours.
Narcissistic Personality Disorder
Features of this disorder include an inability to comfort oneself or to empathize with others as well as a need for admiration and an oversensitivity to criticism or defeat.
Psychological conditions such as post traumatic stress disorder, panic disorder, phobias and depression have all been associated with abnormal eating habits, as have life stressors such as job loss, divorce, or coping with bullying or a learning difficulty such as dyslexia. Stressful or upsetting situations such as tight deadlines at work, school or university or experiencing the death of a loved one are all examples of factors that may contribute to the development of an eating disorder.
Body Image Disorders
Body image disorders such as body dysmorphic disorder, where an individual has a distorted view of their body, or muscle dysmorphia which describes an obsession with muscle mass, are often associated with anorexia or bulimia.
The impact of the media in Western culture can fuel a desire for or obsession with the idea of becoming thin. In the media, thinness or slimness is often equated with success and popularity, which may cultivate and encourage the idea of being thin, especially among young girls. However, the media also fiercely markets cheap and calorific foods, which can cause confusion and stress. Pressure to become thin may also be perceived by individuals who take part in competitive or athletic activities such as modelling, ballet or running.
As a result, people can develop unrealistic expectations for their body image and place an overemphasis on the importance of being thin.
A bodily system called the hypothalamic-pituitary-adrenal axis (HPA) may play an important role in eating disorders.
The HPA releases regulators of appetite, stress and mood such as serotonin, norepinephrine, and dopamine. Abnormalities of these chemical messengers are considered to play an important role in eating disorders. Serotonin is important in the control of anxiety and appetite while norepinephrine is a stress regulator and dopamine plays a role in reward-seeking behaviour. An imbalance of serotonin and dopamine may help to explain why people with anorexia do not derive a sense of pleasure from food and other common comforts.