What is abnormal?

When is behaviour abnormal? Psychologists often use the four Ds:

• Deviance: different from what is usual or expected;
• Distress: causing suffering to the person;
• Dysfunction: interfering with daily life, like work and relationships;
• Danger: risky to the person or to others.

Two main views:

• Deviation from social norms: abnormal behaviour breaks the society's rules. Problem: norms differ between cultures and change over time, and being different is not the same as being ill.
• Maladaptive behaviour: behaviour is abnormal when it harms the person's well-being and growth, whatever the norms. This is the more useful view.

There is no clear 'ideal model' of normal behaviour. Abnormal means maladaptive, not just different.

History: three views have kept recurring:

• Supernatural: disorders caused by evil spirits, treated by exorcism (and in India, by the ojha or faith healer).
• Biological: disorders caused by the body: Galen's humours in Greece; imbalance of doshas in ayurveda.
• Psychological: disorders caused by problems in thinking and feeling.

Over time: in the Middle Ages, demonology dominated, and the mentally ill were often persecuted. In the Renaissance, Johann Weyer argued that so-called 'witches' needed medical, not religious, treatment. The Reform Movement brought humane treatment in asylums; later came deinstitutionalisation: caring for recovered patients in the community instead of locking them in hospitals. Today, psychologists use a bio-psycho-social approach: biology, mind and society together.

Classification: the American Psychiatric Association's DSM-5, and the World Health Organization's ICD-10, which is the system officially used in India.