IB DP Psychology: Option: Abnormal psychology – Study Guide

Abnormal psychology studies patterns of thought, emotion and behaviour that cause distress or impair everyday life. This option asks three connected questions: how do we decide that someone has a psychological disorder, what causes disorders, and what treatments help. You need theories and studies for each, and you must be able to evaluate them, particularly with regard to validity, culture and ethics.

Where this fits in the specification

Abnormal psychology is one of the options in IB Diploma Programme Psychology, studied after the core approaches. The option is organised around three areas: factors influencing diagnosis, the aetiology (causes) of abnormal psychology, and treatment. You apply them to disorders such as depression, anxiety and trauma-related conditions, and you assess them in extended-response questions. Check the current guide for the exact disorders and required content.

Factors influencing diagnosis

Concepts of normality

There is no single agreed definition of abnormality. Common criteria are:

• Statistical infrequency: behaviour that is rare in the population. It is objective but fails because some rare traits, such as high intelligence, are not disorders and some common conditions are.
• Deviation from social norms: behaviour that breaks the unwritten rules of a society. Norms vary between cultures and change over time.
• Maladaptive behaviour or failure to function: behaviour that prevents a person coping with daily life, together with personal distress. This is useful clinically, but some people with a disorder do not feel distress.
• Deviation from ideal mental health: a person lacks qualities such as autonomy and a positive self-view. Few people reach this ideal and it is culturally bound.

Classification systems

Clinicians use classification systems to describe symptoms and make diagnoses. The two main ones are the DSM (Diagnostic and Statistical Manual of Mental Disorders, published by the American Psychiatric Association, current edition DSM-5) and the ICD (International Classification of Diseases, published by the World Health Organization, current edition ICD-11). They list disorders, symptoms and criteria, such as the number of symptoms required and the length of time they last. Classification allows communication, research and access to treatment, but it also risks labelling and stigma.

Validity and reliability of diagnosis

A diagnosis is reliable if different clinicians reach the same conclusion (inter-rater reliability) or the same clinician reaches it on different occasions. It is valid if it measures a real, distinct condition. Evidence has questioned both. In the US-UK diagnostic project, psychiatrists in New York diagnosed schizophrenia more often than those in London from the same cases, which suggested that diagnostic practice varies by country. Rosenhan (1973) reported that people with no disorder, who said they heard a voice, were admitted to psychiatric hospitals and then behaved normally yet were not identified by staff. The study is often criticised for its methods and for its interpretation, but it raised questions about how context shapes diagnosis, labelling and the stigma that follows.

Culture, gender and other influences

Culture affects how symptoms are expressed and understood. Some conditions are described as culture-bound, found in or best understood within specific societies, and a clinician from a different culture may misdiagnose. Bias can also arise from gender, ethnicity and the clinician’s expectations. Overdiagnosis, underdiagnosis and self-diagnosis are other concerns, and so is the way that a diagnosis can influence how people see themselves.

Aetiology of abnormal psychology

Disorders are usually explained at several levels, and explanations are often combined in a diathesis-stress or biopsychosocial model.

• Biological: genetic factors, studied in twin and family studies, show that relatives of a person with a disorder are more at risk, but concordance in identical twins is below 100 per cent, so environment also matters. Neurotransmitters such as serotonin are linked to depression and anxiety. The gene-environment interaction was shown by Caspi and colleagues (2003), who found that people with a particular version of the serotonin transporter gene were more likely to become depressed after stressful life events, which supports diathesis-stress.
• Cognitive: how a person thinks affects emotion. Beck described the negative cognitive triad (a negative view of the self, the world and the future) and negative schemas in depression. Seligman’s learned helplessness theory proposes that experiencing uncontrollable events leads to passivity, which was tested on animals and so raises questions about generalising to people.
• Sociocultural: social factors such as poverty, family conflict, trauma and stressful life events can contribute. Brown and Harris (1978) studied women in a London district and found that severe life events and vulnerability factors, such as the lack of a close confiding relationship, were associated with depression. Cultural factors affect the way symptoms are described and the stigma attached to them.
• Evaluation: each explanation can describe only a part of the picture. Correlation does not show cause, retrospective data can be inaccurate, and reductionist accounts may ignore other levels.

Treatment

Treatments may be biomedical, psychological or group and community based.

• Biomedical treatments include drugs such as selective serotonin reuptake inhibitors (SSRIs), which raise the level of serotonin available at the synapse, and electroconvulsive therapy used in severe cases. Drugs can work quickly and are easy to deliver, but they may have side effects, treat symptoms rather than causes and be affected by the placebo effect. Some meta-analyses, for example Kirsch and colleagues (2008), found that the advantage of antidepressants over placebo was small except in severe depression.
• Psychological treatments include cognitive behavioural therapy (CBT), which helps people to identify and change unhelpful thoughts and behaviours, and has evidence of benefit for depression and anxiety. It needs motivation and time, and its success depends on the therapist and the client.
• Group and community approaches use support groups, community services and family involvement, and they can address social causes and isolation.
• Cultural considerations: treatment should fit the person’s culture and beliefs. Some people prefer traditional or religious support, and therapy may need to be adapted.
• Choosing treatment: severity, preference, access, cost and the evidence all matter, and a combination of drug and psychological treatment is common.

Worked example: planning an extended response

Question: “Discuss two explanations for one disorder.”

1. Choose the disorder and state it clearly. Here: depression.
2. Select two explanations from different levels so there is contrast, such as a cognitive account (Beck’s negative triad) and a biological account (serotonin and gene-environment interaction, Caspi and colleagues, 2003).
3. For each explanation, give a clear outline in your own words, then a study: aim, method, key finding and what it shows about the explanation. Accuracy matters more than the number of studies.
4. Discuss: compare the two. The cognitive account explains how people interpret events, but it may reflect the effects of depression rather than its cause. The biological account recognises vulnerability, but the effect of any single gene is small and it cannot explain why stress matters. Say whether the two can work together in a diathesis-stress model.
5. Conclude with a judgement that answers the question and keep the whole answer organised. IB extended responses are marked on knowledge and understanding, use of research, critical thinking and organisation, so allocate your time to all four.

Common mistakes

• Giving a description of a disorder instead of answering the question set.
• Treating a diagnosis as proof that the disorder exists in the same way in every culture.
• Describing Rosenhan’s study without evaluating its methods.
• Confusing validity (does it measure what it claims) and reliability (is it consistent).
• Saying that a biological factor determines a disorder, instead of increasing vulnerability.
• Using studies about animals without noting the limits on generalisation.

Exam technique

Pay attention to the command term. Discuss needs a balanced view with different arguments, evaluate needs a judgement about strengths and limitations, and to what extent needs a conclusion about degree. Always name the disorder or approach asked about. Use research selectively and link it to the claim you are making. If you cannot recall details of a study accurately, describe the finding in general terms instead of inventing details.

Check your understanding

1. Name two criteria for defining abnormality. For example, statistical infrequency and deviation from social norms.
2. Which two classification systems are widely used? The DSM and the ICD.
3. Give one reason diagnosis might lack validity. For example, symptoms vary with culture, or the labels may not reflect distinct conditions.
4. What does the negative cognitive triad consist of? A negative view of the self, the world and the future.
5. What is the diathesis-stress model? A disorder arises when a vulnerability (diathesis) combines with stress.
6. Outline how SSRIs are thought to work. They raise the level of serotonin available at the synapse by blocking its reuptake.
7. Give one limitation of CBT. It requires motivation and time, and results depend on the therapist and client.

Frequently asked questions

What are the three areas of the IB Psychology abnormal psychology option? The option is organised around factors influencing diagnosis, the aetiology (causes) of abnormal psychology, and treatment.

What are the DSM and the ICD? They are the two main classification systems. The DSM is published by the American Psychiatric Association (current edition DSM-5) and the ICD by the World Health Organization (current edition ICD-11).

What is the difference between reliability and validity of diagnosis? A diagnosis is reliable if different clinicians, or the same clinician on different occasions, reach the same conclusion. It is valid if it identifies a real, distinct condition.

How are IB Psychology extended responses marked? IB extended responses are marked on knowledge and understanding, use of research, critical thinking and organisation, so plan your time to cover all four.