Despite popular belief, the etiology of an eating disorder is not solely based on the psychosocial effect of the media or popular culture. There is no denying that the thinness of pop-icons has the ability to influence some young women and does tend to exacerbate a negative body image (or underlying pathology). However, in recent years psychologists have discovered preexisting vulnerabilities such as personality traits, cognitive functioning, and even neurobiology that help explain why certain people fall victim to maladaptive eating. Anorexic women for example, seem to have a particular type of personality, degree of pathology and a neurobiological difference from the average female.
Anorexia nervosa (AN) is classified by a refusal to maintain body weight above a minimum average, a distorted body image and an intense fear of gaining weight even though clinically underweight (Hebebrand & Remschmidt, 1995). Symptoms of AN typically include severe appearance anxiety, extensive exercising, and intense caloric restriction (Davis et al., 1997). Anorexia nervosa is divided into two subgroups: restrictive AN (R-AN), and binging / purging AN (B/P-AN). R-AN expresses itself through severe caloric restriction as well as excessive exercising, while B/P-AN shows a restrictive caloric intake as well as occasional fits of uncontrollable eating and then purging (Treasure et al., 2003). While males do occasionally suffer from anorexia, women are more afflicted in the general population. Although generally onsetting in adolescence, girls as young as eight can suffer from the disorder (with occasionally weight preoccupation occurring in as young as five years old) (Lask & Bryant-Waugh, 2000). Some believe AN to be a spectrum disorder and to be the final point from volitional dieting to uncontrollable impulses and compulsions (as cited in Davis et al., 1997). The switch from volitional to compulsive is facilitated by individual variables of personality traits, cognitive structures and neurobiology.
Those suffering from AN often have a personality disorder (40-70%) as well; many of which fall into the range of a Cluster C disorder (avoidant, passive aggressive, obsessive compulsive, dependent) (Davis et al., 1997, Davis et al., 1998). Obsessive compulsive disorder and borderline personality disorder are among the most commonly found personality disorders, while avoidant personality and empathy disorders exist within AN sufferers to a lesser extent (Rastam et al., 1995). In addition to personality disorders, individuals frequently possess the traits of needing to conform, obsessive compulsive features, rigidity and perfectionism (Westen & Harnden-Fischer, 2001). Perfectionism and obsessionality, above all others, seem to have the most impact on the development and perpetuation of anorexia nervosa. With the trait of perfectionism, women set unreasonable goals for themselves that are unreachable. They often are self critical, anxious, guilt ridden and competitive (Westen & Harnden-Fischer, 2001). Even after those with AN have "recovered", the trait of perfectionism persists; this implies that the trait may exist before the onset of the disorder, and may be an accelerating feature to its development (Claridge & Davis, 2003). Perfectionism seems to both induce and perpetuate AN, but does not compare to the effects of obsessionality.
An obsessive personality is a necessity in perpetuating anorexic behaviors. Like perfectionism, obessionality is a stable feature before the onset of AN, during, and even after the individual has regained weight (Treasure et al., 2003). This personality trait contributes considerably to the obsessive compulsive tendencies of those with AN, and prevalence of obsessive compulsive disorder (OCD). Obsessive tendencies such as over exercising, weight checking, calorie counting are all similar to OCD (Claridge & Davis, 2003). The over exercising component of R-AN is present in 40-80% of individuals, mostly occurring at the acute phase of their disorder (Holtkamp et al., 2004). The perseverance of obsessive and intrusive thoughts leads to an increase in the amount of exercising; and it is easy to see how someone with an obsessive personality can fall into the pattern of over exercising and caloric restriction (Davis et al., 1998). Obsessionality and the lack of control over the disorder may contribute to creating a treatment-resistant form of anorexia, where perfection and obsession come together to a destructive end (Davis & Kaptien, 2006). Also, obsessionality may contribute to the self defeating and negative affect that afflict those with AN.
Both perfectionism and obsessionality together are a lethal combination. These personality traits often lead to low self esteem and ruminations about the self that are uncontrollable. Self evaluation within AN individuals is based on body shape and weight; because of their perfectionist traits, they are unable to achieve their ideals. Anorexic sufferers have a higher level of negative self evaluation than the average female (Treasure et al., 2003). The self discrepancy theory (Strauman et al., 1991) attempts to explain the reasons behind the negative self evaluation. This theory divides the self into three portions: the actual (attributes the individual believes to possess), ideal (attributes the individual wants to possess), and the ought (attributes the individual feels she ought to possess). The discrepancies between the ideal, ought, and the actual self leads to emotional distress and maladaptive behaviors (while trying to correct this inconsistency) (Strauman et al., 1991). Maladaptive eating behaviors are likely to evolve from conditions of continual negative self evaluation and dissatisfaction over appearance. Those with strong idealized and ought selves have a vulnerability towards severe negative self evaluation and thus, anorexia.
Although personality traits and cognitive precepts often lead to eating disorders such as AN, they are merely phenotypic manifestations of the disorder. Neurobiology also plays a role in this drama of AN vulnerability. However, with the neurobiological theories of AN vulnerability, it becomes difficult to separate cause from effect. For example, starvation and excessive exercising cause certain neurobiological changes (specifically an increase in 5-HT) that make the activity self perpetuating (Claridge & Davis, 2003; Davis et al., 1998). There has been some evidence to suggest that those who suffer from AN may have higher baselines of serotonin 5-HT (before the onset of the disorder) because of its relation to constraint and rigidity (Lask & Bryant-Waugh, 2000). The disturbance in 5-HT, which is responsible for suppressing food intake, is persist after recovery (Treasure et al., 2003). Also, increased 5-HT is associated with obsessive compulsive tendencies (which also do not dissipate after recovery) (Davis et al., 1998). In addition to the increased serotonin levels, those with anorexia may have a preexisting addictive personality which would perpetuate (if not facilitate) the disorder. Deficits within the common reward pathway may lead to an anhedonic personality, and therefore an inability to derive pleasure from food or other primary reinforcers. Exercising releases beta endorphins and dopamine which may compensate for this deficit, but become addicting in the process (Claridge & Davis, 2003).
Anorexia nervosa is a multifaceted disorder, with its etiology far outstretching psychosocial factors. The disorder arises subjectively, with no simple pathway to follow from volition to compulsion. One girl may be driven by her borderline personality disorder, another may feel compelled by her self evaluations, while yet another may find comfort in over exercising to increase DA in her neurobiological system. Because of the subjectiveness of this disorder, researchers are faced with the difficult task of identifying the exact cause for onset and perpetuation (when there are several). Personality traits, cognitive precepts and neurobiology are only the tip of the iceberg for the individual vulnerability of having an eating disorder.
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