BY: Leigh Brosof

DATE: 4 August 2017

Comorbidity is when two or more psychiatric disorders co-occur (or happen together) in the same individual, either at the same time or at different times (lifetime comorbidity).¹ In individuals with eating disorders, comorbidity is common: with up to 97% of individuals with eating disorders also having another psychiatric disorder at some point in their lives.¹ Some of the most common comorbid disorders that occur with eating disorders are anxiety disorders, depression, obsessive-compulsive disorder, and substance use disorders.¹ Comorbidity is important because instead of treating one disorder, clinicians and patients have to be sure to address both (or all) disorders for treatment to be optimally effective.

So, why is comorbidity so common in eating disorders? Although this question has no definitive answer and researchers continue to investigate explanations, one clue might be found in transdiagnostic risk factors. Transdiagnostic risk factors are personality traits, cognitions, or emotions that increase risk for multiple psychiatric disorders.² Because, by definition, transdiagnostic risk factors cross-cut multiple psychiatric disorders, they may help us understand how two (or more) disorders develop together and may be efficient targets for treating comorbid conditions.² Below are more in depth discussions of three recognized transdiagnostic risk factors (although there are many others!) that commonly occur in eating disorders: perfectionism, rumination, and negative urgency.

1. Perfectionism

Perfectionism is a multi-dimensional construct, meaning that there are different parts, or dimensions, that come together to lead to perfectionism.³ One dimension of perfectionism is concern over mistakes, or the excessive worry over making errors.⁴ Someone high in concern over mistakes may equate even a small mistake with total failure. Concern over mistakes is also associated with obsessive-compulsive disorder and anxiety disorders.⁵ Failing to meet a perfectionistic ideal may result in mood changes or changes in behavior that can increase risk for developing psychiatric disorders.⁵ For example, concern over mistakes can extend to eating behaviors, weight goals, or exercise goals and can lead to more disordered eating behaviors when impossible standards cannot be met.

2. Rumination

Rumination is when an individual perseverates on (thinks over and over about) an event that happened, usually in a negative way.⁶ For instance, someone may continually think over an interaction with a coworker (e.g., “Why did I say that? My coworker probably thinks badly of me now.”) In addition to eating disorders, rumination is related to depression, anxiety disorders, and other psychiatric disorders.⁷ By perseverating on negative thoughts, rumination may change a person’s mood and behavior and can increase risk for multiple psychiatric disorders.⁶ In eating disorders, for instance, people with eating disorders may ruminate about how many calories they ate or how much exercise they got, which can perpetuate and intensify eating behaviors and thoughts.

3. Negative Urgency

Negative urgency, a component of impulsivity, is the predisposition to act rashly in response to negative emotions.⁸ An individual high on negative urgency may engage in negative coping behaviors that increase risk for psychiatric disorders such as substance use disorders or bulimia nervosa. Individuals high on negative urgency may, for example, feel compelled to react to distress by binge-eating or purging, as they may not have the ability to respond in a more measured way. The same holds true for someone who may react to distress by turning to alcohol or drugs. A transdiagnostic approach to treatment could target negative urgency by imparting distress tolerance skills that use healthier and more effective approaches for dealing with unpleasant situations.

Understanding and addressing transdiagnostic risk factors may inform more effective treatment for eating disorders, as well as comorbid conditions. For instance, an intervention for perfectionism has been shown to decrease disordered eating, symptoms of anxiety, and depression.⁹ Exploring these cross-cutting risk factors is an important research and treatment direction given the frequency with which individuals with eating disorders also suffer from other psychiatric disorders, even after their eating disorder has resolved.

References:

1. Blinder, B. J., Cumella, E. J., & Sanathara, V. A. (2006). Psychiatric comorbidities of female inpatients with eating disorders.Psychosomatic Medicine, 68(3), 454-462.
2. Nolen-Hoeksema, S., & Watkins, E. R. (2011). A heuristic for developing transdiagnostic models of psychopathology: Explaining multifinality and divergent trajectories.Perspectives on Psychological Science, 6(6), 589-609.
3. Frost, R. O., Marten, P., Lahart, C., & Rosenblate, R. (1990). The dimensions of perfectionism.Cognitive Therapy and Research, 14(5), 449-468.
4. Bulik, C. M., Tozzi, F., Anderson, C., Mazzeo, S. E., Aggen, S., & Sullivan, P. F. (2003). The relation between eating disorders and components of perfectionism.American Journal of Psychiatry, 160(2), 366-368.
5. Egan, S. J., Wade, T. D., & Shafran, R. (2011). Perfectionism as a transdiagnostic process: A clinical review.Clinical Psychology Review, 31(2), 203-212.
6. Cowdrey, F. A., & Park, R. J. (2012). The role of experiential avoidance, rumination and mindfulness in eating disorders.Eating Behaviors, 13(2), 100-105.
7. McLaughlin, K. A., & Nolen-Hoeksema, S. (2011). Rumination as a transdiagnostic factor in depression and anxiety.Behaviour Research and Therapy, 49(3), 186-193.
8. Cyders, M. A., & Smith, G. T. (2008). Emotion-based dispositions to rash action: positive and negative urgency.Psychological Bulletin, 134(6), 807-828.
9. Handley, A. K., Egan, S. J., Kane, R. T., & Rees, C. S. (2015). A randomised controlled trial of group cognitive behavioural therapy for perfectionism.Behaviour Research and Therapy, 68, 37-47.