Mental Health Terms

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There are currently 20 names in this directory beginning with the letter D.

Deterioration in a person’s ability to cope with life stresses, which may lead to the development of symptoms of psychological distress.

Defensive Functioning Scale

A test which is used to assess automatic psychological processes (or coping styles) which protect the person against anxiety and from the awareness of internal or external dangers or stressors.


A disorder of mental processes accompanying organic brain disease. It may include illusions, hallucinations or extreme excitement.

Delirium tremens

Delirium associated with excessive use of alcohol, usually seen as a withdrawal symptom. Features include anxiety, tremors, sweating and vivid and terrifying visual and sensory hallucinations.


Irrational belief that cannot be altered by rational argument. In mental illness it is often a false belief that the person is persecuted by others, or is a victim of physical disease.


A chronic or persistent disorder of the mental processes due to organic brain disease. It is marked by short term memory loss, changes in personality, deterioration in personal care, impaired reasoning ability and disorientation.

Dependence on substance

The physical and/or psychological effects produced by the habitual taking of certain drugs, including alcohol, leading to a compulsion to continue to take the drug.

Dependent Personality Disorder

A disorder with a pervasive and excessive need to be taken care of that leads to submissive and clinging behaviour and fears of separation. This pattern begins by early adulthood.

Depersonalisation Disorder

A disorder in which the person feels unreal or strangely altered, or that the mind is becoming separated from the body. The person may feel like an automaton or as if he or she is living in a dream or a movie.

Depression (psychiatric diagnosis)

A mental state characterised by excessive sadness. Activity may be agitated and restless or slow and retarded. The person may experience feelings of worthlessness, despair and extreme pessimism. There are usually disruptions to sleep, appetite and concentration.

Depressive episode – major

The essential feature of a major depressive episode is a period of at least two (2) weeks during which there is either depressed mood or the loss of interest or pleasure in nearly all activities. In children and adolescents, the mood may be irritable rather than sad.


A chronic condition that makes a person unable to perform in a usual manner.

Disability support services

A range of service responses which enable the individual to live as independently as possible and be included in the ordinary life of their community.

Disorganised type of Schizophrenia

A disorder with disorganised speech, disorganised behaviour and flat or inappropriate mood. The disorganised speech may be accompanied by silliness and laughter that are not closely related to the content of the speech.


The process whereby thoughts and ideas can be split off from consciousness and may function independently, thus allowing conflicting opinions to be held at the same time about the same object.

Dissociative Fugue

A disorder in which the person leaves home or usual surroundings and wanders aimlessly, with inability to recall some or all of ones past. This is accompanied by confusion about personal identity or even the assumption of a new identity.

Dissociative Identity Disorder (formerly Multiple Personality Disorder)

The presence of two (2) or more distinct identities or personality states that recurrently take control of behaviour. In children, the symptoms cannot be attributed to imaginary playmates or other fantasy play.

Disthimic Disorder

A chronically depressed mood that occurs for most of the day, more days than not, for at least two (2) years. Individuals with Disthimic Disorder describe their mood as sad or ‘down in the dumps’. In children the mood may be irritable rather than depressed and required minimum duration is only one (1) year.

District mental health service

A structure that provides a range of specialist mental health service components delivered by specialist mental health professionals to a geographically defined population.


Diagnostic and Statistical Manual of Mental Health Disorders 4th Edition.

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