Comorbidity is generally defined as the co-occurrence of two or more physical or mental health problems (Degenhardt, Hall & Lynkey, 2003). Psychiatric comorbidities, particularly, have emerged as significant clinical, public health and research issues, in part due to recent changes in psychiatric nomenclature, in where there has been increased focus upon elucidating any number of mental health problems with which an individual might present, rather than diagnosing one problem to the exclusion of others (Degenhardt, Hall & Lynkey, 2003). This article will outline to most recent research on psychiatric and medical co-morbidities associated with eating disorders.
Psychiatric Co-Morbidity and Mortality
Psychiatric comorbidity in individuals with an eating disorder is common. Research demonstrates that 55 - 97% of individuals diagnosed with an eating disorder, also receive a diagnosis for at least one more psychiatric diagnosis (Blinder, Cumella & Sanathara, 2006; Swanson et al., 2011). The most common psychiatric comorbidities associated with eating disorders include mood disorders such as major depressive disorder, anxiety disorders particularly OCD and social anxiety disorder, post-traumatic stress disorder (PTSD), substance use disorders, sexual dysfunction, and self-harm and suicide ideation (Coelho, Thaler & Steiger, 2015). Worryingly, death by suicide is significantly more prevalent in eating disorders populations compared to the general population. Recent research finds that individuals with anorexia are 31 times more likely to commit suicide than individuals from the general population, and the suicide rate for individuals with bulimia is 7.5 times higher than that of the general population (Preti et al., 2011). Franko et al., (2004) suggests that co-occuring psychiatric conditions, such as depression and substance abuse, increase the risk of suicide for people with eating disorders. To improve the treatment of eating disorders, it is important to understand the timelines and sequencing of onset of psychiatric comorbidities, and to consider the potential impact these comorbidities have on the diagnosis, treatment and prognosis of the eating disorder (Coelho, Thaler & Steiger, 2015).
Medical Co-Morbidity and Mortality
People with eating disorders also frequently present with medical co-morbidities. Individuals with eating disorders can become very unwell and may require access to hospital treatment. Common reasons for hospitalisation include medical complications (rapid weight loss, a very low weight, cardiac irregularities, hypoglycaemia, electrolyte imbalance), extreme and disordered behaviour, for example several days of no nutrition intake, psychological complications such as suicidality or active self-harm and lack of response to outpatient treatment in very underweight patients (Hay et al., 2014). Eating disorders are one of the 12 leading causes of hospitalisation costs due to mental health (NEDC, 2012), with 11% of these admissions being due to life threatening complications (NEDC, 2010). International research shows that hospitalisation for complications related to eating disorders are increasing due to both increases in first admissions as well as readmissions (Wiseman et al., 2000).
Recent research shows that individuals with anorexia nervosa have a mortality rate five times higher than the general population, and those with bulimia nervosa are 50% more likely to die prematurely than those in the general population (Fichter & Quadflieg, 2016).
Anorexia nervosa has serious physical and medical consequences. Short term consequences include fluid depletion, electrolyte imbalance, anaemia, decreased immunity, amenorrhea, low blood pressure, muscle weakness, dehydration, dry hair and skin, low body temperature and the development of lanugo (Athey, 2003; Lock & Kirz, 2013; NEDC, 2015).
If malnutrition is prolonged, anorexia nervosa can impact virtually all major organ systems in the body. Anorexia nervosa can damage the heart, liver and kidneys; it can result in infertility, osteoporosis, and gastrointestinal, hematologic, dermatologic and metabolic complications (Athey, 2003; Lock & Kirz, 2013; NEDC, 2015). Children and adolescents with anorexia nervosa can experience additional physical consequences such as delayed puberty (Hays et al., 2014), and even after recovering from the eating disorder, as adults they are likely to experience significantly higher levels of cardiovascular symptoms, chronic fatigue, pain, neurological problems, and anxiety and depressive disorders which can limit social and economic activities in later life (Lock & Kirz, 2013; Raftis, 2010).
Anorexia nervosa has the highest mortality of any psychiatric disorder, with aggregated annual mortality rates between 5 – 12 times higher than the annual death rate of the general population (Athey, 2003; Fichter & Quadflieg, 2016). Most commonly, the cause of death for individuals with anorexia nervosa is cardiovascular complications (Athey, 2003), however death by suicide is 31 times higher for individuals with anorexia nervosa than it is for those in the general population (Preti et al., 2011).
There are a range of physical and medical consequences associated with bulimia nervosa, many of which are similar to the effects of anorexia nervosa. The most common physical consequences are dental problems, such as the erosion of dental enamel and the development of cavities, which are primarily caused by self-induced vomiting (Craighead et al., 2013; NEDA, 2015, NEDC, 2015). Self-induced vomiting can also result in dehydration, low potassium and electrolyte imbalances, which can lead to irregular heartbeats, heart failure and death. Inflammation of the digestive tract, swollen glands, gastrointestinal rupture and bleeding are also known side effects (NEDA, 2015).
The mortality rate for individuals with bulimia nervosa is also significantly higher than that of the general population. Individuals with bulimia are 50% more likely to die than individuals from the general population (Fichter & Quadflieg, 2016), and they are 7.5 times more likely to commit suicide than individuals from the general population (Preti et al., 2011).
Binge Eating Disorder
The primary physical and medical complications associated with binge eating disorder, are those also associated with overweight and obesity, since individuals with BED are at an increased risk of weight gain. Conditions observed among these individuals include high blood pressure and cholesterol levels, type II diabetes, heart and gallbladder disease, and menstrual and gastrointestinal problems (Craighead et al., 2013; Godwin, 2008; Hudson et al., 2007; Myers & Wiman, 2014).
The incidence of obesity and eating disorders are interrelated beyond the shared physical consequences of overweight and obesity with binge eating disorder. Obesity is both a risk factor for eating disorders and a serious common outcome for individuals with binge eating disorder and bulimia nervosa (Myers & Wiman, 2014). Binge eating disorder and obesity share a number of risk factors including dieting, unhealthy weight-control behaviours and self-esteem issues. Collectively, these factors contribute to body dissatisfaction that is a predictor of both eating disorders and excessive weight gain (van den Berg & Neumark-Sztainer, 2007).
The higher mortality rate for individuals with binge eating disorder is associated with both the physical consequences of overweight and obesity, and a higher suicide rate (Carpenter et al., 2000; Dong, et al., 2006).
Other Specified Feeding and Eating Disorders
The physical and medical morbidities associated with OSFED are diverse and reflect the health consequences associated with anorexia nervosa, bulimia nervosa and binge eating disorder. Common physical health consequences include weight loss, weight gain or weight fluctuations, a compromised immune system, loss or disturbance of menstrual cycles, damage to teeth and gastrointestinal problems associated with purging, and dehydration (Fairweather-Schmidt & Wade, 2014). OSFED is an equally serious mental illness that effects a significant proportion of the eating disorders population (Fairweather-Schmidt & Wade, 2014).
Athey, J. (2003). Medical complications of anorexia nervosa. Primary Care Update for Ob/Gyns, 10(3): 110 – 115.
Blinder, B.J., Cumella, E.J. & Sanathara, V.A. (2006). Psychiatric comorbidities of female patients with eating disorders. Psychosomatic Medicine, 68: 454 – 462.
Carpenter, K.M., Hasin, D.S., Allison, D.B. & Faith, M.S. (2000). Relationships between obesity and DSM-IV major depressive disorder, suicide ideation, and suicide attempts: Results from a general population study. The American Journal of Public Health, 90(2): 251 -257.
Coelho, J.S., Thaler, L. & Howard, S. (2015). Psychiatric comorbidity in diagnosis. In L. Smolak & M.P. Levine (Eds.), The Wiley Handbook of Eating Disorders (pp. 183 – 196). West Sussex: Wiley Blackwell.
Degenhardt, L., Hall, W. & Lynkey, M. (2003). What is comorbidity and why does it occur? In M. Teesson & H. Proudfoot (Eds). Comorbid mental disorders and substance use disorders: epidemiology, prevention and treatment (pp. 10 – 25). Sydney, Australia: University of New South Wales.
Dong, C., Li W-D, Li D. & Price, R.A. (2006). Extreme obesity is associated with attempted suicide: results from a family study. International Journal of Obesity, 30(2): 388 – 398.
Fairweather-Schmidt, A.K. & Wade, T. (2014). DSM-5 eating disorders and other specified eating and feeding disorders: Is there a meaningful differentiation? International Journal of Eating Disorders, 47(5): 524 – 533.
Fichter, M.M. & Quadflieg, N. (2016). Mortality rates in eating disorders – results of a large prospective clinical longitudinal study. International Journal of Eating Disorders, 49(4): 391 – 491.
Franko, D.L., Keel, P.K., Dorer, D.J., Blais, M.A., Delinsky, S.S., Eddy, K.T. & Herzog, D.B. (2004). What predicts suicide attempts in women with eating disorders? Psychological Medicine, 34: 843 – 853.
Godwin, M. (2008). Epidemiology, pathophysiology, and prevention. Obesity, 299(17): 2092 – 2093.
Hay, P., Forbes, D., Madden, S., Newton, R., Sugenor, L., Touyz, S. & Ward, W. (2014). Royal Australian and New Zealand College of Psychiatrist’s clinical practice guidelines for the treatment of eating disorders. Australia and New Zealand Journal of Psychiatry, 48(11): 1 – 32.
Hudson, J.I., Hiripi, E., Pope, H.G. & Kessler, R.C. (2007). The prevalence and correlates of eating disorders in the national comorbidity survey replication. Biological Psychiatry, 61(3): 348 – 358.
Myers, L.L. & Wiman, A.M. (2014). Binge Eating Disorder: A Review of a New DSM Diagnosis. Research on Social Work Practice, 24(1): 86 – 95.
NEDA. (2015). Health Consequences of Eating Disorders (NEDA website). Accessed: https://www.nationaleatingdisorders.org/health-consequences-eating-disorders
Preti, A.R., Camboni, M.V., & Miorro, P. (2011). A comprehensive meta-analysis of the risk of suicide in eating disorders. Acta Psychiatr Scandinavia, 124: 6 – 17.
Raftis, A. (2010). Anorexia Nervosa in adolescence and adults – causes, consequences and methods of treatment. Journal of the American College of Nutrition, 29(4): 437 – 447.
Swanson, S. A., Crow, S. J., Le Grange, D., Swendsen, J., & Merikangas, K. R. (2011). Prevalence and correlates of eating disorders in adolescents: Results from the national comorbidity survey replication adolescent supplement. Archives of General Psychiatry, 68(7), 714–723.
Van den Berg, P. & Neumark-Sztainer, D. (2007). Fat ‘n happy 5 years later: Is it bad for overweight girls to like their bodies? Journal of Adolescent Health, 41(4): 415 – 417.
Wiseman, C.V., Sunday, S.R., Klapper, F., Harris, W.A. & Halmi, K.A. (2000). Changing patterns of hospitalization in eating disorder patients. The International Journal of Eating Disorders, 30(1): 69 – 75.
Back To Top