Abnormality and classification

The essentials

"Abnormal" literally means away from the normal. Psychologists generally use the four Ds to judge abnormality: deviance (behaviour that is different, extreme or unusual), distress (unpleasant and upsetting to the person or others), dysfunction (interfering with daily activities) and danger (to oneself or others). Two basic approaches exist: abnormality as deviation from social norms and abnormality as maladaptive behaviour that interferes with well-being and growth.

Key points

• Historical views: the supernatural or magical view (behaviour due to evil spirits; exorcism used), the biological or organic view (behaviour due to bodily processes) and the psychological view (problems due to inadequacies in thinking, feeling or perceiving).
• Ancient Greek thinkers such as Hippocrates linked abnormal behaviour to bodily factors; during the Middle Ages demonology and superstition dominated; later reform movements led to more humane care.
• Classification groups disorders by shared symptoms so that professionals can communicate, diagnose and plan treatment.
• The DSM (Diagnostic and Statistical Manual of Mental Disorders) is published by the American Psychiatric Association; its fifth edition (DSM-5) and later revisions are the versions in recent use.
• The ICD (International Classification of Diseases) is published by the World Health Organization and includes mental and behavioural disorders.
• Stigma and stereotypes make people hide their problems; understanding disorders reduces stigma.

Exam tips

• In case questions, check which D is described: unusual behaviour is deviance, personal suffering is distress, inability to work is dysfunction, risk of harm is danger.

Common mistakes

• Assuming any unusual behaviour is a disorder; a gifted athlete is unusual but not abnormal.
• Mixing up publishers: DSM by APA, ICD by WHO.