What is Bulimia Nervosa?

Bulimia nervosa is a type of eating disorder characterised by recurring episodes of binge eating in combination with inappropriate compensatory behaviours and an overvaluation of weight and shape.

There are specific criteria put forth by the latest Diagnostic and Statistical Manual of Mental Disorders (DSM-V) that need to be satisfied in order to receive a diagnosis of bulimia nervosa.  The person must display:

1. Recurrent episodes of binge eating, which are characterised by both of the following:
   • Eating, in a discrete period of time (2-hour period), an amount of food that is larger than most people would eat during a similar period of time and under similar circumstances.
   • A sense of loss of control over eating during this episode, i.e., a feeling that one cannot stop eating or control how much or what one is eating.
2. Recurrent inappropriate compensatory behaviours in order to prevent weight gain, such as self-induced vomiting, misuse of laxatives, diuretics, fasting, or compulsive exercise.
3. These behaviours both occur, on average, at least once a week for three months.
4. Regarding weight and shape as central to one’s self-worth (i.e., overvaluation of weight/shape).
5. The disturbance does not occur exclusively during episodes of anorexia nervosa.

Causes of Bulimia Nervosa

The causes of bulimia nervosa are multifaceted and complex, and result from the interplay of various genetic and psychosocial factors.

The more established bulimia nervosa risk factors are:

Genetic Factors

Part of the risk of developing bulimia nervosa is inherited. However, genetics alone do not cause this illness; genes and environment interact to cause bulimia nervosa.

Genetic factors are excellent for explaining why some people, despite being exposed to similar socio-cultural contexts, do and do not go onto develop bulimia nervosa.

Twin studies provide compelling evidence for the role of genetics in bulimia nervosa. For example, heritability estimates have been shown to be as high as 83% for bulimia nervosa, suggesting that only a very small percentage of risk variation can be explained by other factors (e.g., environment)¹Striegel-Moore RH, Bulik CM. Risk factors for eating disorders. American Psychologist 2007; 62(3): 181..

The extent to which one prescribes to socially defined ideals of beauty (i.e., thin-ideal internalisation) – one of the strong psychosocial risk factors for bulimia nervosa – is also heritable.

For example, studies have shown that scores on thin-ideal internalisation were much more similar among identical twins than fraternal twins, suggesting that genes may with interact with the environment to place someone at greater risk for bulimia nervosa²Suisman JL, O’Connor SM, Sperry S, et al. Genetic and environmental influences on thin-ideal internalization. International Journal of Eating Disorders 2012; 45(8): 942-8..

Although in the preliminary stages, research is beginning to show that dysregulation of certain neurotransmitters and hormones such as dopamine, serotonin, ghrelin, and oxytocin may place people at risk for bulimia nervosa³Kaye W. Neurobiology of anorexia and bulimia nervosa. Physiology & Behavior 2008; 94(1): 121-35..

Psychosocial Factors

• Dieting: Dieting, particularly at an early age, is the strongest psychosocial risk factor for bulimia nervosa. Dieting refers to the conscious attempt to restrict food intake to regulate body weight. It takes many forms, including fasting (i.e., skipping meals), restriction (i.e., under eating), and food avoidance (i.e., avoiding specific food). There are multiple complex physiological (e.g., physiological hunger that overrides cognitive control over eating) and psychological (e.g., black and white thinking when a self-imposed diet rule is broken) mechanisms explaining how dieting causes bulimia nervosa⁴Polivy J, Herman CP. Dieting and binging: A causal analysis. American psychologist 1985; 40(2): 193..
• Thin Ideal Internalisation: We live in a society that generally equates attractiveness and beauty with an extremely thin figure. The extent to which a person prescribes to these socially defined ideals of beauty, known as the “thin ideal internalisation” is a risk factor for bulimia nervosa⁵Stice E. Risk and maintenance factors for eating pathology: a meta-analytic review. Psychological Bulletin 2002; 128: 825-48.. Since an ultra slim figure is unrealistic, some women usually go to extreme lengths to try and achieve an approximation of this figure by engaging in harmful weight control behaviours, placing them at risk for bulimia nervosa.
• Perfectionism and low self-esteem: Perfectionism (i.e., setting unrealistically high standards of the self) and low self-esteem (i.e., a general negative view of the self) interact with each other to place people at risk for bulimia nervosa. People with low self-esteem try to manage by setting extremely high standards. There is a mistaken belief that if such standards are met, one will feel “worthy” or “successful”. If someone places importance on their weight or shape, then such standards are pitted in this domain, causing people to do all they can to achieve their weight/shape-related goals, which often includes resorting to dangerous dietary and weight control behaviours⁶Fairburn CG, Cooper Z, Shafran R. Cognitive behaviour therapy for eating disorders: A “transdiagnostic” theory and treatment. Behavior Research and Therapy 2003; 41: 509-28..
• Stress: Stress that results from various life events can place people at risk for bulimic behaviours. Biologically, stress increases the release of cortisol, a hormone partially responsible for feeling hungry. The release of cortisol can, therefore, cause people to binge on foods they are trying to avoid⁷Epel E, Lapidus R, McEwen B, Brownell K. Stress may add bite to appetite in women: a laboratory study of stress-induced cortisol and eating behavior. Psychoneuroendocrinology 2001; 26(1): 37-49.. Psychologically, eating makes us feel better and can temporarily block any stress we may be experiencing. However, sometimes people can lose control of their eating under stress, making them prone to developing bulimia nervosa⁸Lavender JM, Wonderlich SA, Engel SG, Gordon KH, Kaye WH, Mitchell JE. Dimensions of emotion dysregulation in anorexia nervosa and bulimia nervosa: A conceptual review of the empirical literature. Clinical Psychology Review 2015; 40: 111-22..
• Parent-perceived childhood overweight: An important familial risk factor for bulimia nervosa occurs when parents perceive their child to be overweight. Family and parental factors have been shown to influence the development of adolescent weight concerns, dieting behaviour, binge eating, and purging. These effects come from family modelling of dieting or weight concerns, and/or actual or perceived (by the adolescent) family pressure to lose weight or be thin. Children who are seen as underweight are also likely to experience pressure to be thin (and therefore prescribe to the thin-ideal), resulting in adverse dietary behaviours⁹Allen KL, Byrne SM, Forbes D, Oddy WH. Risk Factors for Full- and Partial-Syndrome Early Adolescent Eating Disorders: A Population-Based Pregnancy Cohort Study. Journal of the American Academy of Child & Adolescent Psychiatry 2009; 48(8): 800-9..
• Body Dissatisfaction: Body dissatisfaction refers to the negative attitudes held toward the body. Body dissatisfaction places people at risk for bulimia nervosa via its connection to dieting and negative affect. More specifically, body dissatisfaction leads to dieting because of the belief that this is an effective weight control technique, and body dissatisfaction encourages negative affect (a known trigger for binge eating and purging) because appearance is a central evaluative dimension for women¹⁰Stice E. Risk and maintenance factors for eating pathology: a meta-analytic review. Psychological Bulletin 2002; 128: 825-48..
• Childhood abuse: Childhood sexual, physical, and emotional abuse is also a very strong risk factor for bulimia nervosa. It has been theorized that binge eating and purging may be both reactions to the abuse and a set of strategies for coping with negative emotional states that are continuously brought up by the abuse¹¹Caslini M, Bartoli F, Crocamo C, Dakanalis A, Clerici M, Carrà G. Disentangling the association between child abuse and eating disorders: a systematic review and meta-analysis. Psychosomatic medicine 2016; 78(1): 79-90..

Read more on the causes & factors of bulimia nervosa.

Side Effects & Consequences of Bulimia Nervosa

There are a whole host of negative medical, psychological, and social consequences of bulimia nervosa¹²Westmoreland P, Krantz MJ, Mehler PS. Medical complications of anorexia nervosa and bulimia. The American journal of medicine 2016; 129(1): 30-7..

• Medical Consequences
  • Dehydration and electrolyte imbalance
  • Erosion of the tooth enamel
  • Gingivitis (gum disease)
  • Oesophagus damage
  • Cardiac arrest
  • Peptic ulcers (sores in the lining of the stomach)
  • Stomach rupture
  • Pancreatitis
  • Infertility
  • Loss of menstruation for females
• Psychological Consequences
  • Depression
  • Anxiety
  • Substance abuse
  • Low self-esteem
  • Self-harm behaviours
  • Suicide
  • Self-hatred
• Social Consequences
  • Social withdrawal/isolation
  • Interpersonal conflict
  • Inability to maintain intimate relationships
  • Sexual dysfunction

Read more on the consequences & side effects of bulimia nervosa.

Treatments for Bulimia Nervosa

There are a wide range of treatments available for bulimia nervosa. Some of these treatments have a stronger evidence base than others. Some people respond differently to different treatments, but, unfortunately, research has to conclusively identify the best determinants of outcomes.

Some of the more widely used treatments for bulimia nervosa are:

Cognitive-Behaviour Therapy

Cognitive-Behaviour Therapy is the recommended first-line treatment for bulimia nervosa all over the world. It is a manual-based treatment lasting around 16-20 sessions with a therapist.

It is based on a model that specifies the factors that maintain bulimia nervosa. These maintaining factors are: overvaluation of weight and shape/ extreme dietary restraint/ maladaptive emotion regulation strategies.

Cognitive-Behaviour Therapy, therefore, devotes all of its effort toward disrupting these 3 maintaining mechanisms. It does so via a collection of different treatment strategies, including:

• Self-monitoring
• Regular eating
• Weekly weighing
• Problem solving
• Exposure techniques
• Relapse prevention

Cognitive-Behaviour Therapy is the most widely studies bulimia nervosa treatment, with dozens of randomized controlled having been conducted. The key findings from meta-analyses of these trials are:¹³Linardon J, Wade T. How many individuals achieve symptom abstinence following psychological treatments for bulimia nervosa? A meta-analytic review. International Journal of Eating Disorders 2018; 51: 287-94.¹⁴Linardon J, Wade T, De la Piedad Garcia X, Brennan L. The efficacy of cognitive-behavioral therapy for eating disorders: A systematic review and meta-analysis Journal of Consulting and Clinical Psychology 2017; 85: 1080–94.¹⁵Linardon J, Wade T, De la Piedad Garcia X, Brennan L. Psychotherapy for bulimia nervosa on symptoms of depression: A meta-analysis of randomized controlled trials International Journal of Eating Disorders 2017; 50: 1124–36.¹⁶Linardon J, Brennan L. The effects of cognitive‐behavioral therapy for eating disorders on quality of life: A meta‐analysis. International Journal of Eating Disorders 2017; 50: 715–30.:

• Cognitive-Behaviour Therapy is more effective than other established treatments such as interpersonal psychotherapy and antidepressant medication
• Improvements from Cognitive-Behaviour Therapy are made mostly in the first month of treatment.
• Improvements are sustained more than a year after Cognitive-Behaviour Therapy ends
• Of those who complete the full course of Cognitive-Behaviour Therapy, 43% completely stop binge eating and purging.
• Cognitive-Behaviour Therapy can also effectively enhance wellbeing and reduce co-occurring depressive symptoms.

Interpersonal Psychotherapy

Interpersonal psychotherapy (IPT) may also be effective for bulimia nervosa

The main aim of Interpersonal psychotherapy is to enrich the quality of social relationships in this population

The reason for this is that interpersonal problems are considered to be very important in contributing to various bulimic behaviours (e.g., binge eating, dietary restriction). Therefore, helping people with their social relationships may indirectly reduce these harmful behaviours.

Interpersonal psychotherapy involves 16 sessions with a therapist, broken up into 3 phases:

1. Phase 1 described the nature of interpersonal psychotherapy and helps patients identify interpersonal problems.
2. Phase 2 addresses interpersonal problems by a collection of therapeutic techniques (e.g., problem solving, role play, communication analysis).
3. Phase 3 is concerned with relapse prevention.

The evidence of Interpersonal psychotherapy for bulimia nervosa is less clear, although a small number of randomized controlled trials have demonstrated that:

• Interpersonal psychotherapy can produce large and long-lasting improvements in symptoms of bulimia nervosa¹⁷Fairburn CG, Bailey-Straebler S, Basden S, et al. A transdiagnostic comparison of enhanced cognitive behaviour therapy (CBT-E) and interpersonal psychotherapy in the treatment of eating disorders. Behaviour Research and Therapy 2015; 70: 64-71..
• Interpersonal psychotherapy is slower to act than Cognitive-Behaviour Therapy, but is as equally effective in the long-term¹⁸Fairburn CG, Bailey-Straebler S, Basden S, et al. A transdiagnostic comparison of enhanced cognitive behaviour therapy (CBT-E) and interpersonal psychotherapy in the treatment of eating disorders. Behaviour Research and Therapy 2015; 70: 64-71..
• Around 23% completely abstain from binge eating and purging after Interpersonal Psychotherapy¹⁹Linardon J, Wade T. How many individuals achieve symptom abstinence following psychological treatments for bulimia nervosa? A meta-analytic review. International Journal of Eating Disorders 2018; 51: 287-94..

Dialectical Behaviour Therapy

Dialectical Behaviour Therapy is an emerging treatment being used to treat bulimia nervosa.

It’s primarily concerned with teaching patients a broader repertoire of adaptive emotion regulation skills. This is because Dialectical behaviour therapy views binge eating and purging to occur as a result of faulty emotion regulation strategies.

Dialectical Behaviour Therapy also lasts 20 sessions with a therapist and includes three core modules:

1. Mindfulness
2. Emotion regulation
3. Distress tolerance.

The evidence for Dialectical behavior therapy is preliminary, but research has shown that:

• Dialectical Behaviour Therapy is more effective than no treatment for people with bulimia nervosa²⁰Safer DL, Telch CF, Agras WS. Dialectical behaviour therapy for bulimia nervosa. The American Journal of Psychiatry 2001; 158: 632-4..
• Around 28% of patients who receive Dialectical Behaviour Therapy completely abstain from binge eating and purging²¹Linardon J, Wade T. How many individuals achieve symptom abstinence following psychological treatments for bulimia nervosa? A meta-analytic review. International Journal of Eating Disorders 2018; 51: 287-94..

Read more on the treatments of bulimia nervosa.