Biological Explanations for Anorexia Nervosa

Introducing Anorexia Nervosa

Anorexia nervosa (AN) is an eating disorder. The NHS website indicates people with anorexia exercise excessively and/or eat too little in an attempt to keep their weight as low as possible. Anorexia nervosa is often driven by body-image distortion.

Prevalence of AN

According to the eating disorder charity BEAT, around 1.25 million people suffer from an eating disorder in the UK. Around 10% of those suffer from AN.
More women suffer from AN than men.
AN is usually developed between the ages of 16 and 17.
AN has the highest adolescent mortality rate of any psychological disorder.

Characteristics of AN

The DSM characterises AN with three main symptoms:
- Weight loss linked to strict restriction of calorie intake, to the point where weight is less than 85% of the expected.
- Fear of weight gain and becoming obese.
- Body dysmorphia: distorted perception of self-image.
Individuals with AN believe that they are fat even though they are very thin. They also deny that their low weight causes any serious risks to their health.

Explanations of AN

AN can be explained through biological mechanisms; genetic and neural.
Psychological explanations have also been suggested.

Genetic Explanations for Anorexia Nervosa

Genes may provide an explanation for the cause of anorexia nervosa (AN). Family, twin and adoption studies have been used to show this.

Illustrative background for <b>Holland et al. (1988)</b> - twin study

Illustrative background for <b>Holland et al. (1988)</b> - twin study ?? "content

Holland et al. (1988) - twin study

Holland et al. (1988) studied the concordance rates of AN in twins where at least one twin had a diagnosis.
They found that 56% of identical twins of individuals with AN developed AN themselves, while the rate was only 5% for non-identical twins did.
As identical twins share 100% of their genetic material, these findings suggest that AN has a strong genetic component.

Illustrative background for Adoption studies (<b>Klump et al. (2009)</b>)

Illustrative background for Adoption studies (<b>Klump et al. (2009)</b>) ?? "content

Adoption studies (Klump et al. (2009))

As identical twins also share a developmental environment, adoption studies are more reliable when trying to attribute a cause to genes.
Adoption studies of siblings have supported heritability of eating disorders, with rates of 59%-82% emerging in studies like Klump et al. (2009).

Issues with family, adoption and twin studies

Studies have not been reliably replicated and results have been inconsistent. So actual heritability rates are not known.
Many genetic models try to simplify causation and ignore the interaction of genes with the environment. It is far more likely that there are multiple contributing factors that differ between individuals.

Neural Explanations for Anorexia Nervosa

Anorexia nervosa (AN) may have a neural explanation. Both damage to the hypothalamus and irregular functioning of neurotransmitters dopamine and serotonin have been linked to AN.

Hypothalamus

AN may be caused by hypothalamic malfunctioning, particularly relating to the lateral hypothalamus (LH).
Animal studies show lesions to this area result in a lack of eating.
Recent research hypothesises that people with AN may have reduced blood flow to the LH. But no causal relationship had been found.

Serotonin

Some people with AN have elevated levels of serotonin, which are linked to anxiety.
Serotonin is produced when we eat food, which may explain why starvation sometimes makes people with AN feel better because it lessens their anxiety.
The metabolites produced by serotonin breakdown have been shown to exist at low levels in AN sufferers. This suggests the serotonin mechanisms are abnormal in these individuals.
But no causal relationship between serotonin mechanisms and AN has been discovered.

Dopamine

Some people with AN have been shown to have overactive dopamine receptors in the basal ganglia.
This may explain why some people with AN have indicated that they don't find eating food pleasurable because increased levels of dopamine in the basal ganglia are linked to abnormal interpretation of rewards.
Aversion to food, loss of weight and body dysmorphia have all been linked to increased dopaminergic activity.

Advantages of neural explanations

There is a lot of stigma surrounding AN and people blame certain factors such as parents, media or the individual.
Biological explanations can remove this blame and show that it is not 'their fault'.
Locating specific biological mechanisms that are disrupted in AN sufferers provides a good basis for treatment. But this can also shed doubt on biological explanations.
E.g. SSRIs - antidepressants that increase the brain’s serotonin uptake - are not effective in treating AN.

1Social Influence

1.1Social Influence

1.1.1Conformity

1.1.2Asch (1951)

1.1.3Sherif (1935)

1.1.4Conformity to Social Roles

1.1.5BBC Prison Study

1.1.6End of Topic Test - Conformity

1.1.7Obedience

1.1.8Analysing Milgram's Experiment

1.1.9Agentic State & Legitimate Authority

1.1.10Variables of Obedience

1.1.11Resistance to Social Influence

1.1.12Minority Influence & Social Change

1.1.13Minority Influence & Social Impact Theory

1.1.14End of Topic Test - Social Influences

1.1.15Exam-Style Question - Conformity

1.1.16Top Grade AO2/AO3 - Social Influence

2Memory

3Attachment

3.1Attachment

3.1.1Caregiver-Infant Interaction

3.1.2Condon & Sander (1974)

3.1.3Schaffer & Emerson (1964)

3.1.4Multiple Attachments

3.1.5Studies on the Role of the Father

3.1.6Animal Studies of Attachment

3.1.7Explanations of Attachment

3.1.8Attachment Types - Strange Situation

3.1.9Cultural Differences in Attachment

3.1.10Disruption of Attachment

3.1.11Disruption of Attachment - Privation

3.1.12Overcoming the Effects of Disruption

3.1.13The Effects of Institutionalisation

3.1.14Early Attachment

3.1.15Critical Period of Attachment

3.1.16End of Topic Test - Attachment

3.1.17Exam-Style Question - Attachment

3.1.18Top Grade AO2/AO3 - Attachment

4Psychopathology

4.1Psychopathology

4.1.1Definitions of Abnormality

4.1.2Definitions of Abnormality 2

4.1.3Phobias, Depression & OCD

4.1.4Phobias: Behavioural Approach

4.1.5Evaluation of Behavioural Explanations of Phobias

4.1.6Depression: Cognitive Approach

4.1.7OCD: Biological Approach

4.1.8Evidence for the Biological Approach

4.1.9End of Topic Test - Psychopathy

4.1.10Exam-Style Question - Phobias

4.1.11Top Grade AO2/AO3 - Psychopathology

5Approaches in Psychology

5.1Approaches in Psychology

5.2Comparison of Approaches (A2 only)

5.2.1Psychodynamic Approach

5.2.2Cognitive Approach

5.2.3Biological Approach

5.2.4Behavioural Approach

5.2.5End of Topic Test - Comparison of Approaches

6Biopsychology

6.1Biopsychology

6.1.1Nervous System Divisions

6.1.2Neuron Structure & Function

6.1.3Neurotransmitters

6.1.4Endocrine System Function

6.1.5Fight or Flight Response

6.1.6The Brain (A2 only)

6.1.7Localisation of Brain Function (A2 only)

6.1.8Studying the Brain (A2 only)

6.1.9CIMT (A2 Only) & Postmortem Examinations

6.1.10Biological Rhythms (A2 only)

6.1.11Studies on Biological Rhythms (A2 Only)

6.1.12End of Topic Test - Biopsychology

6.1.13Top Grade AO2/AO3 - Biopsychology

7Research Methods

7.1Research Methods

7.1.1Experimental Method

7.1.2Observational Techniques

7.1.3Covert, Overt & Controlled Observation

7.1.4Self-Report Techniques

7.1.5Correlations

7.1.6Exam-Style Question - Research Methods

7.1.7End of Topic Test - Research Methods

7.2Scientific Processes

7.2.1Aims, Hypotheses & Sampling

7.2.2Pilot Studies & Design

7.2.3Questionnaires

7.2.4Variables & Control

7.2.5Demand Characteristics & Investigator Effects

7.2.6Ethics

7.2.7Limitations of Ethical Guidelines

7.2.8Consent & Protection from Harm Studies

7.2.9Peer Review & The Economy

7.2.10Validity (A2 only)

7.2.11Reliability (A2 only)

7.2.12Features of Science (A2 only)

7.2.13Paradigms & Falsifiability (A2 only)

7.2.14Scientific Report (A2 only)

7.2.15Scientific Report 2 (A2 only)

7.2.16End of Topic Test - Scientific Processes

7.3Data Handling & Analysis

7.3.1Types of Data

7.3.2Descriptive Statistics

7.3.3Correlation

7.3.4Evaluation of Descriptive Statistics

7.3.5Presentation & Display of Data

7.3.6Levels of Measurement (A2 only)

7.3.7Content Analysis (A2 only)

7.3.8Case Studies (A2 only)

7.3.9Thematic Analysis (A2 only)

7.3.10End of Topic Test - Data Handling & Analysis

7.4Inferential Testing

7.4.1Introduction to Inferential Testing

7.4.2Sign Test

7.4.3Piaget Conservation Experiment

7.4.4Non-Parametric Tests

8Issues & Debates in Psychology (A2 only)

8.1Issues & Debates in Psychology (A2 only)

8.1.1Culture Bias

8.1.2Sub-Culture Bias

8.1.3Gender Bias

8.1.4Ethnocentrism

8.1.5Cross Cultural Research

8.1.6Free Will & Determinism

8.1.7Comparison of Free Will & Determinism

8.1.8Reductionism & Holism

8.1.9Reductionist & Holistic Approaches

8.1.10Nature-Nurture Debate

8.1.11Interactionist Approach

8.1.12Nature-Nurture Methods

8.1.13Nature-Nurture Approaches

8.1.14Idiographic & Nomothetic Approaches

8.1.15Socially Sensitive Research

8.1.16End of Topic Test - Issues and Debates

9Option 1: Relationships (A2 only)

9.1Relationships: Sexual Relationships (A2 only)

9.1.1Sexual Selection & Human Reproductive Behaviour

9.1.2Intersexual & Intrasexual Selection

9.1.3Evaluation of Sexual Selection Behaviour

9.1.4Factors Affecting Attraction: Self-Disclosure

9.1.5Evaluation of Self-Disclosure Theory

9.1.6Self Disclosure in Computer Communication

9.1.7Factors Affecting Attraction: Physical Attributes

9.1.8Matching Hypothesis Studies

9.1.9Factors Affecting Physical Attraction

9.1.10Factors Affecting Attraction: Filter Theory 1

9.1.11Factors Affecting Attraction: Filter Theory 2

9.1.12Evaluation of Filter Theory

9.1.13End of Topic Test - Sexual Relationships

9.2Relationships: Romantic Relationships (A2 only)

9.2.1Social Exchange Theory

9.2.2Evaluation of Social Exchange Theory

9.2.3Equity Theory

9.2.4Evaluation of Equity Theory

9.2.5Rusbult’s Investment Model

9.2.6Evaluation of Rusbult's Investment Model

9.2.7Relationship Breakdown

9.2.8Studies on Relationship Breakdown

9.2.9Evaluation of Relationship Breakdown

9.2.10End of Topic Test - Romantic relationships

9.3Relationships: Virtual & Parasocial (A2 only)

9.3.1Virtual Relationships in Social Media

9.3.2Evaluation of Reduced Cues & Hyperpersonal

9.3.3Parasocial Relationships

9.3.4Attachment Theory & Parasocial Relationships

9.3.5Evaluation of Parasocial Relationship Theories

9.3.6End of Topic Test - Virtual & Parasocial Realtions

10Option 1: Gender (A2 only)

10.1Gender (A2 only)

10.1.1Sex, Gender & Androgyny

10.1.2Gender Identity Disorder

10.1.3Biological & Social Explanations of GID

10.1.4Biological Influences on Gender

10.1.5Effects of Hormones on Gender

10.1.6End of Topic Test - Gender 1

10.1.7Kohlberg’s Theory of Gender Constancy

10.1.8Evaluation of Kohlberg's Theory

10.1.9Gender Schema Theory

10.1.10Psychodynamic Approach to Gender Development 1

10.1.11Psychodynamic Approach to Gender Development 2

10.1.12Social Approach to Gender Development

10.1.13Criticisms of Social Theory

10.1.14End of Topic Test - Gender 2

10.1.15Media Influence on Gender Development

10.1.16Cross Cultural Research

10.1.17Childcare & Gender Roles

10.1.18End of Topic Test - Gender 3

11Option 1: Cognition & Development (A2 only)

11.1Cognition & Development (A2 only)

11.1.1Piaget’s Theory of Cognitive Development 1

11.1.2Piaget's Theory of Cognitive Development 2

11.1.3Schema Accommodation Assimilation & Equilibration

11.1.4Piaget & Inhelder’s Three Mountains Task (1956)

11.1.5Conservation & Class Inclusion

11.1.6Evaluation of Piaget

11.1.7End of Topic Test - Cognition & Development 1

11.1.8Vygotsky

11.1.9Evaluation of Vygotsky

11.1.10Baillargeon

11.1.11Baillargeon's studies

11.1.12Evaluation of Baillargeon

11.1.13End of Topic Test - Cognition & Development 2

11.1.14Sense of Self & Theory of Mind

11.1.15Baron-Cohen Studies

11.1.16Selman’s Five Levels of Perspective Taking

11.1.17Biological Basis of Social Cognition

11.1.18Evaluation of Biological Basis of Social Cognition

11.1.19Important Issues in Social Neuroscience

11.1.20End of Topic Test - Cognition & Development 3

11.1.21Top Grade AO2/AO3 - Cognition & Development

12Option 2: Schizophrenia (A2 only)

12.1Schizophrenia: Diagnosis (A2 only)

12.1.1Classification & Diagnosis

12.1.2Reliability & Validity of Diagnosis

12.1.3Gender & Cultural Bias

12.1.4Pinto (2017) & Copeland (1971)

12.1.5End of Topic Test - Scizophrenia Diagnosis

12.2Schizophrenia: Treatment (A2 only)

12.2.1Family-Based Psychological Explanations

12.2.2Evaluation of Family-Based Explanations

12.2.3Cognitive Explanations

12.2.4Drug Therapies

12.2.5Evaluation of Drug Therapies

12.2.6Biological Explanations for Schizophrenia

12.2.7Dopamine Hypothesis

12.2.8End of Topic Test - Schizoprenia Treatment 1

12.2.9Psychological Therapies 1

12.2.10Psychological Therapies 2

12.2.11Evaluation of Psychological Therapies

12.2.12Interactionist Approach - Diathesis-Stress Model

12.2.13Interactionist Approach - Triggers & Treatment

12.2.14Evaluation of the Interactionist Approach

12.2.15End of Topic Test - Scizophrenia Treatments 2

13Option 2: Eating Behaviour (A2 only)

13.1Eating Behaviour (A2 only)

13.1.1Explanations for Food Preferences

13.1.2Birch et al (1987) & Lowe et al (2004)

13.1.3Control of Eating Behaviours

13.1.4Control of Eating Behaviour: Leptin

13.1.5Biological Explanations for Anorexia Nervosa

13.1.6Psychological Explanations: Family Systems Theory

13.1.7Psychological Explanations: Social Learning Theory

13.1.8Psychological Explanations: Cognitive Theory

13.1.9Biological Explanations for Obesity

13.1.10Biological Explanations: Studies

13.1.11Psychological Explanations for Obesity

13.1.12Psychological Explanations: Studies

13.1.13End of Topic Test - Eating Behaviour

14Option 2: Stress (A2 only)

14.1Stress (A2 only)

14.1.1Physiology of Stress

14.1.2Role of Stress in Illness

14.1.3Role of Stress in Illness: Studies

14.1.4Social Readjustment Rating Scales

14.1.5Hassles & Uplifts Scales

14.1.6Stress, Workload & Control

14.1.7Stress Level Studies

14.1.8End of Topic Test - Stress 1

14.1.9Physiological Measures of Stress

14.1.10Individual Differences

14.1.11Stress & Gender

14.1.12Drug Therapy & Biofeedback for Stress

14.1.13Stress Inoculation Therapy

14.1.14Social Support & Stress

14.1.15End of Topic Test - Stress 2

15Option 3: Aggression (A2 only)

15.1Aggression: Physiological (A2 only)

15.1.1Neural Mechanisms

15.1.2Serotonin

15.1.3Hormonal Mechanisms

15.1.4Genetic Factors

15.1.5Genetic Factors 2

15.1.6End of Topic Test - Aggression: Physiological 1

15.1.7Ethological Explanation

15.1.8Innate Releasing Mechanisms & Fixed Action Pattern

15.1.9Evolutionary Explanations

15.1.10Buss et al (1992) - Sex Differences in Jealousy

15.1.11Evaluation of Evolutionary Explanations

15.1.12End of Topic Test - Aggression: Physiological 2

15.2Aggression: Social Psychological (A2 only)

15.2.1Social Psychological Explanation

15.2.2Buss (1963) - Frustration/Aggression

15.2.3Social Psychological Explanation 2

15.2.4Social Learning Theory (SLT) 1

15.2.5Social Learning Theory (SLT) 2

15.2.6Limitations of Social Learning Theory (SLT)

15.2.7Deindividuation

15.2.8Deindividuation 2

15.2.9Deindividuation - Diener et al (1976)

15.2.10End of Topic Test - Aggression: Social Psychology

15.2.11Institutional Aggression: Prisons

15.2.12Evaluation of Dispositional & Situational

15.2.13Influence of Computer Games

15.2.14Influence of Television

15.2.15Evaluation of Studies on Media

15.2.16Desensitisation & Disinhibition

15.2.17Cognitive Priming

15.2.18End of Topic Test - Aggression: Social Psychology

16Option 3: Forensic Psychology (A2 only)

17Option 3: Addiction (A2 only)

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