Daze

Confusion characterised by lack of clarity

Decentration

The ability to focus simultaneously on several aspects of a problem

Declarative memory

The remembering of factual information. Declarative memory is usually considered explicit

Deductive reasoning

The process by which a particular conclusion is drawn from a set of general premises or statements

Defence mechanisms

Behaviours that protect people from anxiety

Deindividuation

The tendency of people in a large, arousing, anonymous group to lose inhibitions, sense of responsibility, and self-consciousness

Deinstitutionalisation

The trend toward providing treatment through community-based outpatient clinics rather than inpatient hospitals

Déjà vu

The experience of thinking a new situation already occurred

Delusion

An erroneous belief held in the face of contrary evidence

Dementia

A condition characterised by several significant psychological deficits

Depression

A sunken or lowered geological formation

Developmental norms

The median ages at which children develop specific behaviours and abilities

Developmental psychology

The branch of psychology that studies the social and mental development of children

Diabetes

A condition caused by a deficiency of insulin

Diathesis

The constitutional predisposition to a particular disease or abnormality

Diagnostic and Statistical Manual of Mental Disorders (DSM)

A reference book used by psychologists and psychiatrists to diagnose psychological disorders

Dialectical reasoning

A process of going back and forth between opposing points of view in order to come up with a satisfactory solution to a problem

Dichromat

A person who is sensitive to only two of the three wavelengths of light

Disorganised type

A subtype of schizophrenia characterised by disorganized behaviour, disorganised speech, and emotional flatness or inappropriateness

Displacement

A defence mechanism that involves transferring feelings about a person or event to someone or something else

Dissociative disorders

Disorders characterised by disturbances in consciousness, memory, identity, and perception

Dissociative fugue

A disorder in which a person suddenly and unexpectedly leaves home, fails to remember the past, and becomes confused about their identity

Dissociative identity disorder

A disorder in which a person fails to remember important personal information and has two or more identities or personality states that control behaviour. It is also called multiple personality disorder

Dissonance theory

A theory that proposes that people change their attitudes when they have attitudes that are inconsistent with one another

Dopamine

A monoamine neurotransmitter found in the brain and essential for the normal functioning of the central nervous system; as a drug (trade names Dopastat and Intropin) it is used to treat shock and hypotension

Dysphoria

Abnormal depression and discontent