What causes bulimia?

There are a number of theories as to what causes bulimia, but the exact cause of the condition is unknown. There are several factors that may have a role to play in the development of the condition, these include:

Biological Factors

Neurotransmitters

The functioning and levels of the neurotransmitters serotonin and dopamine are thought to play a role in the development of bulimia nervosa as follows:

• Serotonin: Serotonin is linked to weight regulation and eating behaviour. Research shows that altered serotonin (5-HT) in the brain contributes to impaired mood, appetite and impulse control in those suffering from anorexia or bulimia nervosa⁵.
• Dopamine: Dopamine activity is linked to the distortion of body image. It is believed that a 7-repeat allele of the human dopamine receptor D4 (or simply put, a mutation of this gene) is linked to binge eating and bulimia as well as weight gain in bulimia sufferers⁶.

Hormones

Although hormonal abnormalities may be a result of binging and purging in bulimia rather than the cause of it, complex, abnormal interactions between appetite stimulating peptides (neuropeptide Y (NP-Y) and peptide Y (PYY)) and appetite suppressing factors (cholecystokinin (CCK) and beta-endorphin) exist and play a role in the condition⁶.

Genetics

No definite inheritance pattern has been identified to date, however genetic factors do appear to play a role in the development of bulimia. Further genetic studies are needed to explore this association.

It is also thought that those suffering from bulimia nervosa may be predisposed to decreased suppression of ghrelin and cholecystokinin (hunger hormones) after meals which hinders satiety and may lead to behaviours characteristic of the eating disorder.

Developmental factors

Developmental factors involved in bulimia nervosa include:

• Childhood trauma, neglect or abuse
• Anxiety experienced in childhood (any situation that induces severe anxiety such as separation anxiety
• Psychological abuse, even if subtle due to bullying, teasing or interactions that induce feelings of vulnerability and self-doubt.

Psychological factors

Issues relating to mental and emotional health can contribute to the development of bulimia. These include:

• Poor self-esteem
• Perfectionism
• Distorted body image
• Difficulties with impulse control and self-regulation
• Poor coping skills

Risk factors in the development of bulimia

There are a few risk factors that may increase one’s chances of developing bulimia, some of these include⁷: 

• Age – Bulimia is known to develop in men and women between the ages of 18 and 19, therefore, age is a risk factor in the development of the condition. The body changes and matures under hormonal influences during the adolescent years and this is a time when certain individuals are more susceptible to issues with body image and feeling pressured to look a certain way.
• Gender – Girls and women have a higher chance of developing bulimia and other eating disorders than men². Experts believe that this may be due to women dieting more than men. Those who restrict calories often begin to have their cravings heightened, which in turn may lead to bingeing and purging thereafter due to feelings of guilt. Women have also been recorded as being more likely than men to experience a negative perception of their bodies. This may be linked to women being more susceptible to the social pressures placed on them by society and the media.
• Genetic predisposition and biological makeup – It is generally considered that those with relatives of the first degree (i.e. siblings, children or parents) with an eating disorder may have a higher risk of developing an eating disorder. This suggests that there may be a genetic link to these disorders. While those who have relatives with bulimia have a higher risk of the disorder, it is also thought that these people may have inherited rigidity and perfectionism, factors that play a role in bulimia itself, as personality traits.
  
  In terms of biological factors, some experts believe a serotonin deficiency may also have a role to play in the development of the condition.

**My Med Memo – Serotonin is a vital chemical neurotransmitter produced by nerve cells in the body. The chemical sends signals between the nerve cells and is most found in one’s digestive tract. Serotonin is created from an amino acid known as tryptophan, this amino acid enters the body through one’s diet and is found in foods such as red meats, nuts and cheese. Serotonin affects the functioning of the muscles, endocrine and cardiovascular systems and plays a role in appetite, sexual desire, mood, memory, temperature and body functioning. If serotonin levels are disrupted, all of these functions may be impacted.

Having a higher body mass index (BMI) or being overweight as a young child or teenager may also increase one’s risk of bulimia.

• Emotional and physiological issues –Low self-esteem, anxiety disorder and depression may contribute to bulimia. Affected individuals tend to have certain triggers for episodes of bingeing, these may include:
  • Boredom
  • Stress (including financial stress in the family)
  • Poor body image
  • Restrictive dieting
  • Cravings for food
  • Traumatic events
• Societal and media pressure – The media and social pressures of society may have a significant role to play in the way people feel about themselves. Models and actors seem to promote the idea of fame being associated with being sexually attractive in having an aesthetically pleasing body. These body standards change depending on the fashions and popular culture of the time, however, it is clear that body standards created by the media put a great deal of pressure on society which may lead to issues with body image and in turn, eating disorders.
• Work, artistic or sports pressures – Actors, dancers, models and athletes tend to have a higher risk than other of developing bulimia. Parents and coaches may put an immense amount of pressure on people in these fields to lose weight for aesthetic and performance-based reasons.

 

^References:

^{2. NCBI. Eating Disorder. Available: https://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0051873/ [Accessed 27.10.2017]}

^{5. NCBI. 2009. Eating disorders: the current status of molecular genetic research. Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2839487/ [Accessed 26.02.2018]}

^{6. Eating Disorders. 1999. Leptin, Neuropeptide Y, and Peptide YY in Long-Term Recovered Eating Disorder Patients. Available: http://eatingdisorders.ucsd.edu/research/pub/imaging/doc/1999/gendall1999leptin.pdf [Accessed 26.02.2018]}

^{7. NCBI. 1996. Challenges in the treatment of colonic motility disorders. Available: https://www.ncbi.nlm.nih.gov/pubmed/8931827 [Accessed 26.02.2018]}