a b c d e f g h i k l m n o p r s t u
v w z
daily hassles: The relatively minor yet chronic and persistent
life stressors that combine to have a strong, negative influence on
defence mechanisms: In psychoanalytic theory, reality-distorting
strategies unconsciously adopted to protect the ego from anxiety.
deinstitutionalization: The increasing tendency for treatment
to take place in the community, perhaps on an outpatient basis, rather
than having patients reside in a public institution, such as a provincial
delay of reward gradient: The learning theory term for the finding
that rewards and punishments lose their effectiveness the further they
are removed in time from the response in question.
delayed echolalia: See echolalia.
delirium: A state of great mental confusion in which consciousness
is clouded, attention cannot be sustained, and the stream of thought
and speech is incoherent. The person is probably disoriented, emotionally
erratic, restless or lethargic, and often has illusions, delusions,
delirium tremens (DTs): One of the withdrawal symptoms that sometimes
occurs when a period of heavy alcohol consumption is terminated; marked
by fever, sweating, trembling, cognitive impairment, and hallucinations.
delusional (paranoid) disorder: A disorder in which the individual
has persistent persecutory delusions or delusional jealousy and is very
often contentious but has no thought disorder or hallucinations.
delusional jealousy: The unfounded conviction that one’s mate
is unfaithful; the individual may collect small bits of "evidence"
to justify the delusion.
delusions: Beliefs contrary to reality, firmly held in spite
of evidence to the contrary; common in paranoid disorders; of control,
belief that one is being manipulated by some external force such as
radar, television, or a creature from outer space; of grandeur,
belief that one is an especially important or powerful person; of
persecution, belief that one is being plotted against or oppressed
dementia: Deterioration of mental faculties—memory, judgment,
abstract thought, control of impulses, intellectual ability—that impairs
social and occupational functioning and eventually changes the personality.
See Alzheimer’s disease.
dementia praecox: An older term for schizophrenia, chosen to
describe what was believed to be an incurable and progressive deterioration
of mental functioning beginning in adolescence.
demographic variable: A varying characteristic that is a vital
or social statistic of an individual, sample group, or population, for
example, age, sex, socioeconomic status, racial origin, education.
demonology: The doctrine that a person’s abnormal behaviour is
caused by an autonomous evil spirit.
denial: Defence mechanism in which a thought, feeling, or action
is disavowed by the person.
dependent personality disorder: Lacking in self-confidence, such
people passively allow others to run their lives and make no demands
on them so as not to endanger these protective relationships.
dependent variable: In a psychological experiment, the behaviour
that is measured and is expected to change with manipulation of the
depersonalization: An alteration in perception of the self in
which the individual loses a sense of reality and feels estranged from
the self and perhaps separated from the body. It may be a temporary
reaction to stress and fatigue or part of panic disorder, depersonalization
disorder, or schizophrenia.
depersonalization disorder: A dissociative disorder in which
the individual feels unreal and estranged from the self and surroundings
enough to disrupt functioning. People with this disorder may feel that
their extremities have changed in size or that they are watching themselves
from a distance.
depression: A disorder marked by great sadness and apprehension,
feelings of worthlessness and guilt, withdrawal from others, loss of
sleep, appetite, sexual desire, loss of interest and pleasure in usual
activities, and either lethargy or agitation. Called major depression
in DSM-IV and unipolar depression by others. It can be an associated
symptom of other disorders.
depressive paradox: A cognitive tendency for depressed individuals
to accept personal responsibility for negative outcomes despite feeling
a lack of personal control.
depressive predictive certainty: This concept, derived from the
hopelessness theory of depression, states that people become prone to
depression when they perceived that an anticipated state of helplessness
is certain to occur.
derealization: Loss of the sense that the surroundings are real;
present in several psychological disorders, such as panic disorder,
depersonalization disorder, and schizophrenia.
descriptive responsibility: In legal proceedings, the judgment
that the accused performed an illegal act. Contrast with ascriptive
deterioration effect: In abnormal psychology, a harmful outcome
from being in psychotherapy.
detoxification: The initial stage in weaning an addicted person
from a drug; involves medical supervision of the sometimes painful withdrawal.
detumescence: The flow of blood out of the genital area.
diagnosis: The determination that the set of symptoms or problems
of a patient indicates a particular disorder.
dialectical behaviour therapy: A therapeutic approach to borderline
personality disorder that combines client-centred empathy and acceptance
with behavioural problem solving, social-skills training, and limit
diathesis: Predisposition toward a disease or abnormality.
diathesis–stress paradigm: As applied in psychopathology, a
view that assumes that individuals predisposed toward a particular mental
disorder will be particularly affected by stress and will then manifest
dichotic listening: An experimental procedure in which a person
hears two different taped messages simultaneously through earphones,
one in each ear, usually with the instruction to attend to only one
of the messages.
diencephalon: The lower area of the forebrain, containing the
thalamus and hypothalamus.
dimensional classification: An approach to assessment according
to which a person is placed on a continuum. Contrast with categorical
directionality problem: A difficulty that arises in the correlational
method of research when it is known that two variables are related but
it is unclear which is causing the other.
discriminative stimulus: An event that informs an organism that
if a particular response is made, reinforcement will follow.
disease: The medical concept that distinguishes an impairment
of the normal state of the organism by its particular group of symptoms
and its specific cause.
disease model: See medical
disorder of written expression: Difficulties writing without
errors in spelling, grammar, or punctuation.
disorganized attachment style: An attachment orientation in which
the infant demonstrates a confused attachment style that emerges after
being raised in a chaotic and abusive environment.
disorganized schizophrenia: In this subtype of schizophrenia
the person has diffuse and regressive symptoms; the individual is given
to silliness, facial grimaces, and inconsequential rituals and has constantly
changeable moods and poor hygiene. There are few significant remissions
and eventually considerable deterioration. This form of schizophrenia
was formerly called hebephrenia.
disorganized speech (thought disorder): Speech found in schizophrenics
that is marked by problems in the organization of ideas and in speaking
so that others can understand.
disorientation: A state of mental confusion with respect to time,
place, identity of self, other persons, and objects.
displacement: A defence mechanism whereby an emotional response
is unconsciously redirected from an object or concept perceived as dangerous
to a substitute less threatening to the ego.
dissociation: A process whereby a group of mental processes is
split off from the mainstream of consciousness, or behaviour loses its
relationship with the rest of the personality.
dissociative amnesia: A dissociative disorder in which the person
suddenly becomes unable to recall important personal information to
an extent that cannot be explained by ordinary forgetfulness.
dissociative disorders: Disorders in which the normal integration
of consciousness, memory, or identity is suddenly and temporarily altered;
dissociative amnesia, dissociative fugue, dissociative identity disorder
(multiple personality), and depersonalization disorder are examples.
dissociative fugue: Disorder in which the person experiences
total amnesia, moves, and establishes a new identity.
dissociative identity disorder (DID): A rare dissociative disorder
in which two or more fairly distinct and separate personalities are
present within the same individual, each with his or her own memories,
relationships, and behaviour patterns, with only one of them dominant
at any given time. Formerly called multiple personality disorder.
divorce mediation: A form of couples (marital)
therapy in which a distressed couple is helped to collaborate on issues
such as child custody outside the adversarial framework of a formal
dizygotic (DZ) twins: Birth partners who have developed from
separate fertilized eggs and who are only 50 percent alike genetically,
no more so than siblings born from different pregnancies; sometimes
called fraternal twins.
dominant gene: One of a pair of genes that predominates over
the other and determines that the trait it fosters will prevail in the
dopamine: A catecholamine that is both a precursor of norepinephrine
and itself a neurotransmitter of the central nervous system. Disturbances
in certain of its tracts apparently figure in schizophrenia and Parkinson’s
dopamine activity theory: The view that schizophrenia arises
from an increase in the number of dopamine receptors.
double-bind theory: An interpersonal situation in which an individual
is confronted over long periods of time by mutually inconsistent messages
to which she or he must respond, formerly believed by some theorists
to cause schizophrenia.
double-blind procedure: A method for reducing the biasing effects
of the expectations of research participant and experimenter; neither
is allowed to know whether the independent variable of the experiment
is being applied to the participant.
double depression: A comorbid condition that applies to someone
characterized by both dysthymia and major depression.
Down syndrome (trisomy 21): A form of mental retardation generally
caused by an extra chromosome. The child’s IQ is usually less than 50,
and the child has distinctive physical characteristics, most notably
dream analysis: A key psychoanalytic technique in which the unconscious
meanings of dream material are uncovered.
drive: A construct explaining the motivation
of behaviour, or an internal physiological tension impelling an organism
drug abuse: See substance abuse.
drug addiction: See substance
DSM-IV: The current Diagnostic and Statistical Manual of the
American Psychiatric Association.
dualism: Philosophical doctrine, advanced most definitively by
Descartes, that a human being is both mental and physical and that these
two aspects are separate but interacting. Contrast with monism.
Durham decision: A 1954 U.S. court ruling that an accused person
is not ascriptively responsible if his or her crime is judged attributable
to mental disease or defect.
dysfunction: An impairment or disturbance in the functioning
of an organ, organ system, behaviour, or cognition.
dyslexia: A disturbance in the ability to read; it is one of
the learning disorders.
dyspareunia: Painful or difficult sexual intercourse; the pain
or difficulty is usually caused by infection or a physical injury, such
as torn ligaments in the pelvic region.
dysthymic disorder: State of depression that is long lasting
but not severe enough for the diagnosis of major depression.