Explanations for anorexia nervosa
The neural explanation sees anorexia resulting from abnormally functioning brain mechanisms, especially the insula brain area, which develops differently in anorexics. The neurotransmitter serotonin is associated with the onset and maintenance of anorexia, with leptin and noradrenaline also attracting interest. The genetic explanation sees anorexia as having an inherited component, with several genes involved. The more of these you have, the more vulnerable you are to developing anorexia. The family systems theory sees anorexia resulting from dysfunctional patterns of family interaction. This includes enmeshment, a family interactive style that inhibits each family member’s sense of individuality, and autonomy and control, which involve the lack of experience of choice and freedom in relation to oneself and others. Social learning theory (SLT) sees anorexia as being learned through the observation and imitation of anorexic behaviour. This involves modelling, where learning occurs vicariously by observation of others, reinforcement, where models incur positive consequences for their anorexic behaviour, and media, where anorexia is portrayed as desirable in public forms of communication. Cognitive theory sees anorexia resulting from maladaptive thought processes, involving distortions, errors in thinking that negatively affect perceptions of body image, and irrational beliefs, maladaptive ideas that lead to the development and maintenance of anorexia.
Fig 13.3 Anorexics often have a distorted body image in line with the cognitive theory
Oberndorfer et al. (2013) assessed the role brain structures play in the development of anorexia. 14 female recovered anorexics (recovered anorexics were used to avoid the confounding variable of altered nutritional state) and 14 non-anorexic females fasted overnight and then each received a standardised breakfast of 604 calories, before having an fMRI scan to test neurocircuitry by measuring brain responses to sweet tastes, where participants were given 120 doses of either sucrose or sucratose (to distinguish between neural processing of calorific and non-calorific sweet tastes). It was found that anorexic participants had greatly reduced responses to sweet tastes, especially the taste of sucrose, in the right anterior insula brain area, which is associated with whether people feel hungry or not. The findings confirmed results from earlier studies that linked anorexia with neural processes in the insula brain area. This suggests that altered functioning of neural mechanisms contributes to the restricted eating feature of anorexia.
• Hakonarson (2010) compared DNA material from anorexics and non-anorexics to find variants of the OPRD1 and HTR1D genes were associated with anorexia, supporting the genetic explanation.
• Strauss & Ryan (1987) found that anorexics had less autonomy than non-anorexics, as well as poorer self-concept and disturbed family interactions, supporting the family systems theory.
• Bemis (1978) found that the weight of centrefolds in ’Playboy’ magazine progressively decreased over a 20-year period, while Garner & Garfinkel (1980) found beauty queen winners had become slimmer over time, supporting the SLT idea that anorexia results from observing and imitating media models of ultra-slim women.
• Bemis-Vitousek & Orimoto (1993) found that anorexics had a consistently distorted body image and felt that they must continually lose weight to be in control of their bodies, supporting cognitive theory, especially the key role that distortions play in the maintenance of anorexia.
SLT is able to explain why anorexia has increased over time, is more prevalent among females and why it only occurs in certain cultures, which adds to its validity as an explanation for the disorder.
The multiple factors of anorexia converge into two key elements: low self-esteem and a high need for perfectionism, both best explained by cognitive theory, adding to its validity as an explanation.
Genes might exert a non-direct influence upon the development of anorexia, as the personality traits associated with the condition, especially perfectionism, may be under genetic influence. This suggests biological and psychological explanations can be combined.
If genes were responsible for anorexia, then concordance rates between MZ twins would be 100 per cent, which they are not. Therefore genetic and environmental factors must be involved.
Rather than heightened family tensions causing anorexia, it may be that having an anorexic in a family leads to heightened tensions, lowering support for the family systems theory.
SLT cannot explain why dieting continues after the point at which compliments for losing weight stop, or indeed when negative comments begin.
Many individuals express dissatisfaction with their bodies and have dieted, but only a few develop anorexia, which cognitive theory cannot explain.
Different explanations suggest different types of therapy for anorexia. For example, leptin therapy, based on neural explanations, family therapy, based on the family systems explanation and cognitive behavioural therapy, based on cognitive theory.