Key characteristics of anorexia nervosa

Anorexia nervosa is a serious eating disorder prevalent in the UK, affecting approximately 1 in 250 females and 1 in 2000 males, often emerging between the ages of 16 and 17. It is characterised by extreme weight loss due to restricted food intake, alongside distorted perceptions and fears related to body weight.

Defining features of anorexia nervosa

• Restricted energy intake - Individuals consume far fewer calories than needed, resulting in a body weight significantly below what is healthy for their age, height, and gender.
• Intense fear of weight gain - There is a profound fear of becoming fat or gaining weight, even when the person is already underweight, often leading to behaviours like excessive exercise or strict dieting to prevent weight gain.
• Distorted body image - Individuals perceive themselves as overweight despite being dangerously thin, place excessive importance on their weight as a measure of self-worth, and often fail to recognise the severity of their low body weight.

Biological explanations for anorexia nervosa

Biological factors, including genetics and neural mechanisms, have been explored as potential causes of anorexia nervosa. These explanations focus on inherited traits and brain functions that may contribute to the disorder.

Genetic factors in anorexia nervosa - Holland et al. (1988)

• Method - Investigated 40 pairs of twins where at least one twin was diagnosed with anorexia nervosa.
• Results - The study found a concordance rate of 56% for identical (monozygotic, MZ) twins, who share nearly all their genetic material, compared to just 5% for non-identical (dizygotic, DZ) twins, who share about half.
• Conclusions - The higher concordance rate in MZ twins suggests a genetic component to anorexia nervosa, though the rate not being 100% indicates other influences are also at play.
• Evaluation - While genetics appear to contribute, environmental factors may also explain the higher rates in MZ twins, as they often share more similar experiences due to their identical appearance. This suggests that genetics alone cannot fully account for the disorder.

Neural mechanisms and anorexia nervosa

• Hypothalamus dysfunction:
  • The lateral hypothalamus, a brain region linked to hunger regulation, may be involved.
  • Studies indicate that damage to this area can lead to a refusal to eat (aphagia) in animals, and individuals with anorexia nervosa show reduced blood flow to this region.
  • However, it remains unclear if this is a cause or a consequence of the disorder.
• Serotonin imbalances:
  • Abnormally high levels of the neurotransmitter serotonin, associated with increased anxiety, are often found in individuals with anorexia nervosa.
  • Since serotonin is influenced by dietary components like amino acids, reducing food intake might lower anxiety, potentially reinforcing starvation behaviours.
  • Again, whether this imbalance causes or results from anorexia is not yet established.

Psychological explanations including family systems theory

Psychological perspectives focus on family dynamics and interpersonal relationships as contributing factors to the development of anorexia nervosa. One prominent theory examines the role of family structure and interactions.

Family systems theory and its impact

• Core concepts of family systems theory - This theory suggests that anorexia nervosa develops within the context of dysfunctional family dynamics, where the disorder reflects broader family issues rather than just individual problems.
• Key family characteristics - Research by Minuchin et al. (1978) identified specific traits in families of individuals with anorexia nervosa:
  • Enmeshment - Overly close emotional bonds blur individual identities, leaving little room for personal autonomy.
  • Overprotectiveness - Excessive control and protection prevent the child from developing independence.
  • Rigidity - Strict family beliefs and loyalty expectations limit flexibility and conflict resolution.
• Supporting evidence - A study by Kramer (1983) compared families of individuals with eating disorders to a control group, finding higher levels of dysfunction in the former, supporting the idea that family dynamics play a role.
• Limitations of the theory - This approach risks blaming families, which could harm the individual's wellbeing if family changes are forced. Additionally, it struggles to explain cases where anorexia nervosa develops after leaving home or in adulthood, as it primarily focuses on young people living with family.

Social learning theory and the role of media in anorexia nervosa

Social learning theory (SLT) posits that behaviours are learned through observing and imitating others, particularly in cultural contexts. This theory is often applied to explain how societal pressures around body image may contribute to anorexia nervosa.

Principles of social learning theory in anorexia nervosa

• Observation and imitation - Individuals, especially young females, observe and mimic behaviours of admired role models, such as celebrities, family members, or peers, who are often portrayed as successful due to their slim figures.
• Cultural ideals of beauty - In Western societies, thinness is frequently equated with beauty and success, reinforcing the desire to emulate such traits.
• Reinforcement mechanisms - Vicarious reinforcement occurs when role models receive praise or attention for their appearance, motivating others to adopt similar behaviours. Direct reinforcement may also happen when family or friends initially compliment weight loss, inadvertently encouraging further restriction.
• Development of anorexia nervosa - Continued weight loss, initially reinforced, can spiral into the extreme behaviours characteristic of anorexia nervosa as the individual seeks ongoing validation.

Research on media influence

• Keel and Klump (2003) study - A comprehensive review of global studies examined the prevalence of anorexia nervosa in relation to media exposure. The findings revealed higher rates of the disorder in countries with stronger Western media influences, though it was present worldwide.
• Conclusions from media research - While Western media appears to contribute to anorexia nervosa prevalence, its universal presence suggests other underlying factors are also involved.
• Strengths of social learning theory - This theory accounts for the rising diagnosis rates of eating disorders over time, correlating with increased media and advertising presence in society.
• Limitations of social learning theory - Not all individuals exposed to the same media pressures develop eating disorders, indicating that SLT alone cannot explain anorexia nervosa. Other factors, such as genetic predisposition or neural issues, must also be considered.

Cognitive theory as an explanation for anorexia nervosa

Cognitive theory focuses on distorted thought patterns and irrational beliefs as central to the development and maintenance of anorexia nervosa. It explores how faulty perceptions influence behaviour and self-image.

Core ideas of cognitive theory

• Distorted self-perception - Individuals with anorexia nervosa often believe they are overweight despite being underweight, viewing their body through a skewed lens.
• Overemphasis on appearance - Self-worth is disproportionately tied to body weight and shape, overshadowing other aspects of identity.
• Irrational beliefs about food - Rigid, unfounded ideas about eating and dieting dominate thinking, such as equating food intake with loss of control.
• Control as self-definition - The ability to restrict eating becomes a primary measure of personal success or value.

Supporting evidence for cognitive theory

• Gardner and Moncrieff (1988) research - This study compared individuals with anorexia nervosa to a control group, finding that those with the disorder were more likely to perceive a digitally unaltered image of themselves as distorted, highlighting the role of cognitive misperceptions in the condition.
• Implications of cognitive distortions - These findings suggest that addressing distorted thinking patterns is crucial for treatment, as they underpin the behaviours and fears associated with anorexia nervosa.