by Erica Morrison
Recently, a great amount of psychological literature has focused on finding biological and genetic causes of mental illnesses and disorders, including eating disorders. However, according to recent twin studies, the heritability component of eating disorders may only account for 0% to 70% of the variance (Fairburn, Cowen, & Harrison, 1999). The leaves an ample amount of room for speculation of possible environmental risk factors for eating disorders. In this paper, I wish to examine one possible environmental risk that has received attention since the mid-80’s. Since that time, researchers have searched to determine the relationship between childhood sexual abuse, or trauma in general, and the development of eating disorders.
It seems somewhat logical to assume that a person who has experienced sexual trauma might develop feelings of dissatisfaction as well as disgust with their own body—the medium of abuse. Also, one might even attribute the anti-pubertal effects achieved through self-starvation as a suppression of sexuality that may be desired by a survivor of sexual abuse. These hypotheses, as well as connections observed between sexual abuse and PTSD and also between anxiety disorders (of which PTSD is one) and eating disorders led many researchers to study this relationship. However, the large body of the studies contradict each other’s findings. Many studies have found no evidence of a relationship between sexual abuse and eating disorders and others have found evidence. In this paper, I would like to examine the results of studies that have been aimed at answering the question, “Is childhood sexual abuse a risk factor for eating disorders?”
Over the past decade or more, many researchers have attempted to answer this question, but were unable to find any positive correlation between the two that was more than for abuse in normal controls. For example, in a study of Japanese women, controls were MORE likely to have experienced minor sexual abuse and the authors conclude, “an abuse history is not essential or prerequisite to developing eating disorders.” (Nagata, Kiriike, Iketani, Kawarada, & Tanaka, 1999). Also, several other studies, including one by Conners and Morse (1993) found that the rates of having experienced abuse were no greater in eating disordered patients than in the general population. More studies suggest that the apparent correlations may be due to the fact that both childhood sexual abuse and eating disturbances are common in the female population (Conners & Morse, 1993; Everill & Waller, 1995; Pope & Hudson, 1992). As observed in a paper by Dansky, Brewerton, Kilpatrick, and O’Neil (1997), authors of three recent studies have concluded that childhood sexual abuse was “not a significant risk factor in the development of bulimia nervosa” (Kinzl, Traweger, Guenther, & Biebel, 1994; Pope, Mangweith, Negrao, Hudson, & Cordas, 1994; Rorty, Yager, & Rossotto, 1994). Overall, many researchers have been unable to conclude, from current data, that childhood sexual abuse is a risk factor, or even distinctively related to eating disorders (Pope & Hudson, 1992).
It must be mentioned however, that these studies include methodological limitations such as dependence on retrospection and self-report measures (Nagata et al., 1999), no comparison group (Pope et al., 1994; Kinzl et al., 1994), small sample size (Pope et al., 1994; Rorty et al., 1994), limited age range of participants (Kinzl et al., 1994; Pope et al., 1994; Rorty et al., 1994), nonrandom sampling (Kinzl et al., 1994; Pope et al., 1994; Rorty et al., 1994), and failure to assess physical assaults which occurred in the absence of sexual assault experiences (Rorty et al., 1994), (Dansky et al., 1997).
On the other hand, some studies’ results contain evidence supporting the existence of a relationship. For example, in a study conducted as part of the National Women’s Study phase III found “significantly higher rates of both sexual and aggravated assault among women with bulimia nervosa”(Dansky et al., 1997). Another study not only attempted to assess the prevalence of childhood abuse survivors with eating disorders, but also how many of those survivors experienced PTSD symptoms as a result (and the effect of PTSD on the severity of eating disorders) (Gleaves, Eberenz, & May, 1998). Although they did not find any significant relationship between PTSD and symptom severity, they did find that the prevalence of trauma was much higher than in the general population. In a study comparing incest victims to nonabused controls, incest victims were more likely to self-report symptoms of bulimia nervosa than control subjects (Wonderlich, Donaldson, Carson, Staton, Gertz, Leach, & Johnson, 1996). Finally, in seven out of eight studies that compared nonclinical bulimic subjects with normal controls, a significant relationship between a history of childhood sexual abuse and eating disturbance was found (Fallon & Wonderlich, 1997).
Because these studies give strength to only one side of an argument, it is important to examine the between-studies discrepancies as well as within-study limitations. First, as noted by Fallon and Wonderlich (1997), varying definitions of sexual abuse and diagnostic measures of the eating disorders complicate the literature. Second, different methods of sampling led to different sampling biases. For example, Dansky et al. (1997) used a telephone interview method to gather data from the general population. It seems likely that many people would be unable or unwilling to disclose information to a stranger on the telephone about being abused – especially if it was very traumatic. Gleaves et al. (1998) took their data from women admitted to a residential treatment facility. Since many eating disordered individuals never have to enter inpatient settings; the sample may reflect a group who suffers more severely than the general population of people with eating disorders. Finally, most other studies were necessarily constrained by retrospective accounts and self-reporting of abuse and perceived trauma.
Other questions surrounding the topic serve to further complicate these already cloudy conclusions. First of all, many results suggest that the experience of childhood sexual trauma is more related to bulimia nervosa than anorexia or eating disorders not otherwise specified. For example, Dansky et al. (1997) found that bulimia nervosa respondents were more likely (though not significantly) to have been raped and to have experienced other types of direct assaults. However, Gleaves et al. (1998) found no relation between type of eating disorder and experience of PTSD symptoms.
A second complication with this topic is that even if all studies found agreement and proof that childhood sexual abuse and eating disorders co-occur at a statistically significant rate, can a risk factor relationship be assumed? As stated by Nagata et al. (1999), “…abuse history might indicate familial dysfunction or a childhood environmental issue.” Furthermore, Fallon and Wonderlich (1997) point out that sexual abuse may be related to many various types of psychopathology and is not specific to eating disorders.
As it stands, positive correlation between sexual abuse and eating disorders has been established in enough studies to warrant further investigation. More research needs to be done in more controlled, valid and reliable methods so that the presence or absence of a relationship may be known. Then, research might examine the possible existence of a third variable, which may account for the seeming correlation. Some other questions worth studying further are whether or not childhood sexual abuse leads to a more severe expression of an eating disorder and more comorbidity with other psychiatric disorders. This may sound like a lot of work is suggested for a relationship that may not even exist. However, given the great difficulty in treating, and lack of effective treatments now available for eating disorders, identifying more etiological risk factors such as discussed in this paper are more than desirable—they are needed.
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