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Abnormal Psychology Unit 1: Defining Abnormality, History and Research Methods

Abnormal psychology is the scientific study of psychological disorders: what counts as a disorder, where ideas about disorder came from, and how researchers study it. This unit gives you the vocabulary and history the rest of the course builds on.

Covers: The four Ds: deviance, distress, dysfunction and danger, Statistical, social-norm and harmful dysfunction definitions, The DSM-5-TR definition of mental disorder and culture, Ancient, medieval and Renaissance views, Asylums, moral treatment and reform, Somatogenic and psychogenic perspectives, Deinstitutionalization and stigma, Research methods and epidemiology

Study guide

No single feature defines abnormality, so textbooks often use the four Ds. Deviance means behavior, thoughts or emotions that differ markedly from a society's norms. Distress means the person suffers, although some disorders (such as a manic episode) may involve little felt distress. Dysfunction means the pattern interferes with daily life, such as work, school or relationships. Danger means risk to self or others; it is dramatic but actually uncommon, and most people with mental disorders are not violent. Each D alone is insufficient. Being a genius is statistically deviant but not a disorder, and grief after a death causes distress but is an expected response. Clinicians look for a pattern that combines several Ds and is not simply a culturally expected reaction.

Several formal definitions try to sharpen this. The statistical definition calls rare behavior abnormal, but it mislabels rare desirable traits and ignores common problems such as depression. The social-norm definition depends on culture and era; homosexuality was listed as a disorder until 1973, showing how norms can embed prejudice. Jerome Wakefield's harmful dysfunction model argues that a disorder requires both a failure of some internal mechanism to perform its natural function and harm judged by social values. The DSM-5-TR defines a mental disorder as a syndrome of clinically significant disturbance in cognition, emotion regulation or behavior that reflects a dysfunction in underlying psychological, biological or developmental processes and is usually associated with significant distress or impairment. It excludes expectable responses to common stressors, culturally approved responses and political, religious or sexual deviance unless they result from a dysfunction.

Ideas about the causes of abnormal behavior have shifted over thousands of years. Skulls from prehistoric sites show trephination, holes bored in the skull, which some scholars interpret as an attempt to release spirits, although the purpose is debated. Hippocrates, in ancient Greece, argued that disorders had natural causes and proposed an imbalance of four humors (blood, phlegm, yellow bile and black bile). In medieval Europe, religious and demonological explanations became more prominent, along with episodes of mass hysteria such as tarantism. During the Renaissance, physicians like Johann Weyer argued that the mind could become sick just as the body could. Asylums, such as London's Bethlehem Hospital (Bedlam), spread in the 1500s and 1600s but often became overcrowded places of confinement rather than treatment.

Reform came in the late 1700s and 1800s with moral treatment. Philippe Pinel in Paris unchained patients and treated them with kindness, and William Tuke founded the York Retreat in England as a humane rural setting. In the United States, Dorothea Dix campaigned for state hospitals, but these later became overcrowded and understaffed. Two perspectives then competed. The somatogenic perspective, that abnormal functioning has physical causes, gained support when general paresis was traced to syphilis infection. The psychogenic perspective, that causes are psychological, grew from Franz Mesmer's work, Jean-Martin Charcot's and Josef Breuer's studies of hypnosis and hysteria, and Sigmund Freud's psychoanalysis. In the 1950s and 1960s, antipsychotic drugs and community mental health policy led to deinstitutionalization, the release of many hospital patients, which helped some people but left others homeless or incarcerated when community services fell short.

Researchers study disorders with several methods. A case study describes one person in depth and generates hypotheses but cannot establish cause or generalize well. Correlational studies measure how strongly two variables move together (r from -1 to +1); they show association, not causation, because of third variables and reverse causation. Experiments randomly assign participants to conditions and manipulate an independent variable, allowing causal conclusions; in treatment research, double-blind placebo-controlled trials guard against expectancy effects. Epidemiology studies how often disorders occur. Prevalence is the proportion of a population that has a disorder during a period (point, 12-month or lifetime), while incidence counts new cases that arise during a period. Longitudinal designs follow people over time, and analogue studies model a disorder in a laboratory or in animals.

Key ideas

• Abnormality is usually judged by a combination of deviance, distress, dysfunction and sometimes danger, not by any one criterion.
• Definitions of disorder are shaped by culture and history, so diagnostic categories change over time.
• The DSM-5-TR requires clinically significant disturbance reflecting an underlying dysfunction, usually with distress or impairment.
• Wakefield's harmful dysfunction model combines a factual element (a failed natural function) with a value element (harm).
• History swings between natural and supernatural explanations, and between humane treatment and confinement.
• General paresis showed that a psychological syndrome could have a biological cause, boosting the somatogenic view.
• Only experiments with random assignment support causal claims; correlations and case studies do not.

Formulas and rules

Common mistakes

• Treating danger as typical of mental disorders; most people with disorders are not violent, and they are more often victims of violence.
• Confusing prevalence (all existing cases) with incidence (only new cases).
• Assuming a strong correlation proves that one variable causes the other.
• Crediting Dorothea Dix or Pinel with deinstitutionalization; deinstitutionalization happened in the mid-1900s, long after moral treatment.
• Thinking a behavior that is statistically rare must be a disorder, or that a common one cannot be.

Before the test, make sure you can

• Explain each of the four Ds and give an example where one D is present without a disorder.
• Compare the statistical, social-norm and harmful dysfunction definitions and name a weakness of each.
• State the key parts of the DSM-5-TR definition of a mental disorder, including its exclusions.
• Identify the main figures in the history of abnormal psychology (Hippocrates, Weyer, Pinel, Tuke, Dix, Mesmer, Charcot, Freud).
• Explain why the discovery of the cause of general paresis mattered for the somatogenic perspective.
• Describe the causes and consequences of deinstitutionalization.
• Calculate prevalence and incidence from described data and tell them apart.
• Evaluate what conclusions a case study, correlational study or experiment can support.

Words to know

Psychopathology

The scientific study of abnormal behavior, thoughts and emotions, and also a term for the disorders themselves.

Deviance

Behavior, thoughts or emotions that differ markedly from a society's ideas about proper functioning.

Distress

Personal suffering or upset; common in disorders but neither necessary nor sufficient for one.

Dysfunction

Interference with the ability to carry out daily activities such as work, self-care or relationships.

Harmful dysfunction

Wakefield's view that a disorder is a failure of an internal mechanism's natural function that causes harm as judged by social values.

Trephination

A prehistoric practice of boring a hole in the skull; some scholars think it was meant to release evil spirits.

Humors

Hippocrates' four bodily fluids (blood, phlegm, yellow bile, black bile) whose imbalance he believed caused disorders.

Moral treatment

A 19th-century approach emphasizing humane, respectful care in a calm setting, associated with Pinel and Tuke.

Somatogenic perspective

The view that abnormal psychological functioning has physical causes.

Psychogenic perspective

The view that the chief causes of abnormal functioning are psychological.

General paresis

A progressive disorder with psychological and physical symptoms, found in the 1800s to be caused by syphilis.

Deinstitutionalization

The mid-20th-century release of large numbers of patients from public mental hospitals into community care.

Prevalence

The proportion of a population that has a disorder during a specified period.

Incidence

The number or rate of new cases of a disorder that arise during a specified period.

Third-variable problem

The possibility that a correlation between two variables is produced by a separate variable that affects both.

Random assignment

Placing participants in conditions by chance so groups are equivalent before the manipulation.

Double-blind design

A study in which neither participants nor experimenters know who receives the real treatment.

Cultural concepts of distress

DSM-5-TR term for ways cultural groups experience, explain and communicate suffering, such as ataque de nervios.

Sample practice questions

30 more questions like these, from level 1 to 5, are in the practice set.