Bulimia nervosa: A brief review
Physical development during childhood and adolescence has multiple impacts on psychological development and functioning, with “normal” growth involving proportional increases in food intake of nutrients and energy (World Health Organization, 1992). Persistent psychopathologies caused by severe disturbances in eating behaviors can thus have long-term, detrimental effects on an individual’s physical and psychological development (World Health Organization, 1992). Eating disorders (EDs) are common, especially in developed countries, and individuals with EDs typically experience high levels of functional impairment, distress and comorbidity with other mental disorders (Berkman, Lohr, & Bulik, 2007). The self-evaluation of individuals with EDs is unduly influenced by body shape and weight – an individual’s perception of their own physical appearance (body image) as well as the degree to which a person is accepting of their physical appearance (body satisfaction) play an important role (Cooper & Fairburn, 1993). In comparison with other mental disorders, EDs are characterized by a greater risk for a chronic course as well as negative outcomes (Berkman et al., 2007). Not only are EDs cited as a major source of morbidity and mortality (Gowers & Bryant-Wagh, 2004), but they also have been linked to severe physical and mental health problems and seriously impaired social functioning in adulthood (Striegel-Moore, Seeley, & Lewinsohn, 2003).
Bulimia nervosa is an eating disorder that is characterized by frequent episodes of binge eating followed by recurrent inappropriate compensatory behaviors aimed at avoiding weight gain (Williams, Watts, & Wade, 2012). According to The Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5; American Psychiatric Association, 2013), binge-eating and compensatory behaviors must both occur, on average, at least once a week for three months in order for there to be a diagnosis of bulimia nervosa. An episode of binge eating is typified by two primary characteristics: first, an individual eats an amount of food that is significantly larger than most people would eat under similar circumstances and during a similar period of time, and second, an individual feels a sense of lack of control over eating during said episode (American Psychiatric Association, 2013). An individual must exhibit over-eating in conjunction with the feeling that he or she is unable to stop eating, control what they eat or how much of it they ingest, reflecting the combination of both behavioral and cognitive symptoms that are included in the criteria for a diagnosis of bulimia nervosa (American Psychiatric Association, 2013). The compensatory behaviors mentioned in the DSM-5 include self-induced vomiting, excessive use of laxatives, diuretics, or other medications, misuse of enemas, fasting, and excessive exercise (American Psychiatric Association, 2013). The most important aspect of these behaviors is that they are aimed at preventing weight-gain and are often referred to as purging (Lampard, Byrne, McLean, & Fursland, 2011). Bingeing and purging can have a multitude of negative impacts on the gastrointestinal system and maladaptive eating behaviors, especially in younger subjects, are detrimental to the proper growth of cognitive, physiological and psychological systems (Gowers, 2006). Depending on the age of onset, the secondary physical problems caused by during critical periods can impede the attainment of proper bone density, target height and other important aspects of development (Micali & House, 2011). The developmental pathway, course and outcome of bulimia vary greatly but all are marked by disturbances in eating behaviors and maladaptive perceptions of body size and shape accompanied by a fear of being fat as well as compensatory behaviors to lose weight or prevent weight gain (Williams et al., 2012).
The prevalence rates of bulimia nervosa in young Western women are estimated at 1% when considering only full diagnosis but have been shown to be as high as 7% when researchers included partial syndromes (Hoek & van Hoeken, 2003). The incidence rates of bulimia are estimated around 12 per 100,000, with the highest reported rates in females between the ages of 20 and 24 years (Hoek & van Hoeken, 2003). Thus, although young teens are generally considered at high risk for developing eating disorders, bulimia tends to manifest later in adolescence. While estimates of prevalence and incidence rates may vary slightly depending on the source, they all reveal a marked gender effect, with women reporting significantly higher rates of the disorder than men. Upon analysis, the distribution between the sexes has been estimated at 10:1 for females versus males (Hoek & van Hoeken, 2003). It is important to note here that this effect could result, in part, from men’s reticence to report mental health issues generally as well as more specifically body-weight issues (Currin, Schmidt, Treasure, & Jick, 2005). The current debate regarding incidence rates among researchers revolves around whether the increase in rates across the 20th century reflects an actual representation of reality or whether this increase can be accounted for by examining external factors such as improved detection and access to services (Currin et al., 2005). While the etiology of eating disorders is thought to be determined by a multitude of factors, past research has suggested the presence of a genetic component (Gowers, 2006; Bulik, C., Sullivan, P., Wade, T., & Kendler, K., 2000). This heredity can influence an individual’s trajectory in a number of ways by predisposing him or her to a combination of physical and psychological vulnerability factors (Gowers, 2006). Physical vulnerabilities include early puberty and obesity while psychological vulnerabilities include personality traits such as a tendency towards perfectionism as well as issues with control and impulsivity (Gowers, 2006). Ultimately, little is certain regarding the epidemiology of bulimia nervosa or what exact role familial factors might play in the etiology of the disorder (Kendler & Maclean et al., 1991). The data collected regarding this area of research into bulimia nervosa varies greatly and these discrepancies suggest that more research must be done (Fairburn, Jones, et al., 1993).
The assessment of bulimia nervosa can be somewhat problematic for clinicians and should utilize a comprehensive, multi-faceted approach that includes interviews with the individual as well as members of his or her familial base (Micali & House, 2011). Clinicians should also engage the individual in self-assessments and a proper medical examination conducted by a trained professional (Micali & House, 2011). Self-report questionnaires used in the assessment of child and adolescent eating disorders include the Children’s Eating Attitude Test (Maloney, McGuire & Daniels, 1988), the Children’s Eating Disorders Inventory (Garner, 1991a) and the Eating Disorder Examination Questionnaire (Fairburn & Beglin, 1994). Other assessment measures include semi-structured interviews like the Children’s Eating Disorder Examination (Bryant-Waugh et al., 1996) and online measures such as the Development and Well-Being Assessment (Goodman et al., 2000; Moya et al., 2005). Eating disorders in general are not self-limiting and bulimia nervosa has a high rate of comorbidity with other psychiatric and medical problems so clinicians should include assessments for the presence of other disorders (Micali & House, 2011).
Treatment for bulimia nervosa includes prevention, both specific and general, as well as intervention (NICE, 2004). Prevention methods involve increasing awareness and understanding of bulimia nervosa in the general population as well as targeting at-risk groups, especially among younger children and adolescents, with special programs that can also be adopted by families (NICE, 2004). It is important that schools include education regarding healthy living, appropriate diet, body image and other issues related to eating disorders in adolescents in their curricula (NICE, 2004). In regards to intervention, psychotherapy is often a clinician’s first choice of treatment for bulimia nervosa, although access to these types of interventions for patients can be limited and prohibitive (Eynde & Schmidt, 2008). Alternative forms of self-guided therapy may provide a solution to these barriers, although the research regarding self-help strategies is limited (Eynde & Schmidt, 2008). Cognitive behavioral therapy (CBT) has been identified as the gold standard in regards to the treatment of bulimia nervosa, with guidelines suggesting that the program offered be comprised of 16 to 20 sessions over the course of 4 or 5 months (Gowers, 2006). Other treatment options that have been studied include interpersonal psychotherapy (IPT) and pharmacological interventions (Eynde & Schmidt, 2008).
Fairburn, Marcus & Wilson (1993) developed a specific form of CBT (CB-BN) to address both aspects of bulimia nervosa: the behaviors as well as the distorted cognitions related to body image and body satisfaction. This model is the most commonly used form of CBT applied in the treatment of patients with bulimia and continues to be expanded upon so as to appropriately reflect all of the mechanisms associated within the disorder (NICE, 2004; Lampard et al., 2011). This model is based in the idea that individuals who over-value the importance of eating and weight and then base their self-worth in terms of their control over these functions, which can lead to extreme dietary habits aimed at restricting food intake or weight gain (Fairburn, Marcus, & Wilson, 1993). As a result, the individual attempts to adhere to increasingly inflexible rules regarding diet to combat any impulse they may have to eat or put on weight; these often manifest as avoidant or restrictive dietary behaviors (Fairburn, Marcus, & Wilson, 1993). These strict rules often prove too difficult for the individual to follow indefinitely, resulting in subsequent episodes of binge-eating and a loss of control that further serves to perpetuate the individual’s worries regarding weight, shape and control (Fairburn, Marcus, & Wilson, 1993). These concerns continue to grow, especially as a result of binge-eating episodes, which can lead to further dietary restraint as well as the use of compensatory behaviors (Fairburn, Marcus, & Wilson, 1993). The use of compensatory behaviors to modulate the effect of binge eating allows the individual to continue binge eating, creating a feedback loop whereby the binge-purge cycle is maintained (Fairburn, Marcus, & Wilson, 1993). At the heart of the CB-BN model is a system of self-evaluation that is dysfunctional and it is this core aspect of a bulimic individual’s psychology, along with his or her actual bulimic behaviors, that CBT hopes to address.
Numerous studies document the efficacy of CBT as a form of treatment for bulimia nervosa. According to Eynde & Schmidt (2008), upon completion of the CB-BN program according to the guidelines previously listed, approximately 30-40% of patients are found to be symptom-free. In a study conducted by Stewart, Schneider, Arnow, Raeburn and Telch (1989), 56% of patients no longer engaged in binge eating and purging at the end of treatment. They found that CBT was associated with a 77% reduction in the frequency of purging behaviors as well as improvement in other psychopathological areas associated with the disorder (Stewart et al., 1989). Another approach to the treatment of bulimia nervosa explored by this study was response prevention: a tactic whereby patients are exposed to binge foods during a therapy session followed by vomiting prevention (Stewart et al., 1989; Wilson, Rossiter, Kleifeld, & Lindholm, 1986). This approach is based on the theory that purging behaviors serve to reduce anxiety, serving a similar function as might a compulsion (Wilson et al., 1986). By preventing the patient from vomiting in the presence of binge foods, the patient learns that their anxiety will eventually resolve itself over time with no purging required (Wilson et al., 1986). Some research found that patients who receive both CBT and response prevention improved more than patients who only received treatment in the form of CBT, but conflicting data regarding this area of research suggests that not enough is known about the combined effects of CBT and response prevention (Stewart et al., 1989; Wilson et al., 1986).
The interpersonal difficulties often exhibited by individuals with bulimia nervosa have also led researchers to investigate the efficacy of IPT in regards to treatment of the disorder (Eynde & Schmidt, 2008). Although there are benefits associated with IPT, findings suggest that CBT is more useful and effective in the reduction of bulimic symptoms in the short-term (Fairburn, Jones, Peveler, Hope, O’Connor, 1993; NICE, 2004). In general, data reveals that IPT can have positive effects in the long-term but CBT leads to a greater reduction of bulimic symptoms in the short-term as well as higher rates of remission over than its IPT counterpart (Fairburn, Jones, et al., 1993). Given the high comorbidity between bulimia nervosa and affective disorders such as depression, research on pharmacotherapy treatments for bulimia nervosa has primarily focused on antidepressants (Eynde & Schmidt, 2008). Eynde & Schmidt (2008) conducted a systematic review of randomized clinical trials that compared several kinds of tricyclic antidepressants, a selective serotonin reuptake inhibitor, and monoamine oxidase inhibitors. In general, the use of a single antidepressant was shown to be clinically effective in patients with bulimia nervosa and was linked to a greater rate of remission overall (Eynde & Schmidt, 2008). This review also found that there was no significant difference in the efficacy of the various classes of antidepressants, although antidepressant use was generally associated with higher dropout rates (Eynde & Schmidt, 2008). Currently, the US Food and Drug Administration only officially approved the use of fluoxetine in the treatment of bulimia, an antidepressant that has been associated with more acceptable results and lower dropout rates (Eynde & Schmidt, 2008). The use of fluoxetine has been shown to be especially beneficial in patients who did not respond well to the more common forms of psychotherapy (Walsh, Devlin, & Fairburn, 2000). Fluoxetine is associated with the reduction of bulimic symptoms as well as a superior relapse prevention effect (Walsh, Devlin, & Fairburn, 2000). Interestingly enough, findings regarding the combination of psychotherapy and antidepressant treatment in bulimia nervosa are inconsistent with no clear additive effect evident, suggesting that more research must be done in order to fully understand the ways in which psychotherapeutic and pharmacological interventions might interact when used in the treatment of bulimia nervosa (Eynde & Schmidt, 2008; Walsh, Devlin, & Fairburn, 2000).
It is important to note that the majority of the existing data on treatment options available for bulimia nervosa has been collected from adult samples (NICE, 2004; Gowers, 2006). NICE Guidelines (20004) stressed the need for future evidence-based data regarding the application of CBT and other forms of treatment in adolescents with bulimia. Other areas of research identified by NICE (2004) as priorities relate to studies that help clinicians to improve patients’ motivation and patients’ engagement in the treatment the process as well as data on the effect of different treatment settings (e.g in-patient versus out-patient). Since the 2004 publication of NICE, several trials have been conducted specifically using adolescent samples; findings suggest that there is a slight advantage to the use of family therapy over supportive psychotherapy, although evidence also points to the efficacy of guided self-help treatment options (Eynde & Schmidt, 2008; Walsh, Devlin, & Fairburn, 2000). Specific concerns regarding the goodness-of-fit of the CB-BN model when applied to adolescent cases are somewhat alleviated by the prior successful application of CBT to the treatment of depression in adolescents – it is likely that CBT can be similarly adapted for adolescents with bulimia (Gowers, 2006). It is becoming increasingly important to conduct research regarding the etiology, course and treatment of bulimia nervosa, specifically in adolescents, especially given that the last two decades of the 20th century witnessed a rise in incidence and prevalence rates of the disorder (Currin, Shcmidt, Treasure & Lick, 2005). As a result of this trend, primary care and mental health services are faced with increasing demands for treatment that further burden these institutions and their resources (Eynde & Schmidt, 2008). Consequently, current and future research should focus on self-guided programs that alleviate the load placed on facilities and bridge the gap between the supply and demand of treatment (Eynde & Schmidt, 2008; Shapiro, Bauer, Andrews, Pisetski, Bulik-Sullivan, Hamer, & Bulik, 2009). Text messaging programs for self-monitoring of bulimic symptoms that can be placed within the larger context of CBT present an interesting and relevant avenue of research, especially when we consider the treatment of bulimia nervosa in adolescents (Shapiro et al., 2009).