Glossary of Key Terms


Glossary of Key Terms

Bipolar disorder: a mood disorder in which there are depressive and manic (elated) episodes.

Comorbidity: the presence of two or more disorders in a given individual at the same time.

Concordance rate: if one twin has a disorder or condition, the likelihood that the other twin also has it.

Diathesis–stress model: the notion that psychological disorders occur when there is a genetically determined vulnerability (diathesis) and relevant stressful conditions.

Dysthymic disorder: a condition involving depressive symptoms that occur much of the time over a period of at least 2 years.

Electroconvulsive therapy (ECT): a form of therapy used to treat depressed patients, in which brain seizures are created by passing an electric current through the head.

Endocrine system: a system of a number of ductless glands located throughout the body that produce the body’s chemical messengers, called hormones.

Free association: a technique used in psychoanalysis, in which the patient says the first thing that comes into his/her mind.

Learned helplessness: passive behaviour produced by the perception that punishment is unavoidable.

Major depressive disorder: a disorder characterised by symptoms such as sad depressed mood, tiredness, and loss of interest in various activities.

Meta-analysis: an analysis in which all of the findings from many studies relating to a given hypothesis are combined for statistical testing.

Neurotransmitters: chemical substances that are released at the junction between neurons (a synapse) and that affect the transmission of messages in the nervous system.

Placebo effect: positive responses to a drug or form of therapy based on the patient’s beliefs that the drug or therapy will be effective, rather than on the actual make-up of the drug or therapy.

Reinforcement: a behaviour is more likely to re-occur because the response was agreeable. Both positive and negative reinforcement have agreeable consequences.

Reliability: the extent to which a method of measurement or a research study produces consistent findings across situations or over time.

Repression: the process of forcing very threatening thoughts and memories out of the conscious mind in

Freudian theory; motivated forgetting.

Seasonal affective disorder: a disorder that nearly always involves the sufferer experiencing severe depression during winter months.

Treatment aetiology fallacy: the mistaken belief that the effectiveness of a form of treatment indicates the cause of a disorder.

Validity: the extent to which something is true. This can be applied to a measurement tool, such as a psychological test, or to the “trueness” of an experimental procedure both in terms of what goes on within the experiment (internal validity) and its relevance to other situations (external validity).