Schizophrenia key terms

DSM-5

The diagnostic and statistical manual of mental disorders, published by the American Psychiatric Association

ICD-10

International classification of diseases, published by the world health organisation

DSM-5 diagnostic criteria

At least two of the following: Delusions, hallucinations, disorganised speech, grossly disorganised or catatonic behaviour, negative symptoms

Reduction in one or more major areas of functioning

Continuous signs of the disturbance must persist for at least 6 months, during which the patient must experience at least 1 month of active symptoms

Type 1 schizophrenia

Positive symptoms such as hallucinations and delusions

Type 2 schizophrenia

Any behavioural deficit, such as speech poverty (alogia), and avolition (a reduction in interests and desires as well as an inability to initiate and persist in goal-directed behaviour)

Co-morbidity

The presence of one or more additional disorders or diseases simultaneously occurring with schizophrenia

Culture bias

The extent to which the diagnostic system reflects beliefs about what is viewed as normal and acceptable in western, predominantly white culture

Validity

The extent to which the methods used to measure schizophrenia are accurately measuring schizophrenia

Gender bias

Occurs when the accuracy of diagnosis is dependent on the gender of an individual, the diagnostic criteria may be gender-biased or clinicians may base their judgements on stereotypical beliefs about gender

Neural correlates

Measurements of the structure or function of the brain that correlate with an experience, in this case schizophrenia

Dopamine hypothesis

Suggests that schizophrenia is a result of the overactive transmission of the neurotransmitter dopamine

Broca’s area

An area of the brain responsible for speech production, in which an excess of dopamine has been found which may lead to auditory hallucinations

Enlarged ventricles

Patients with schizophrenia may have enlarged ventricles (the fluid filled gaps between brain areas), which is associated with damage to central brain areas and the prefrontal cortex

Genetic explanation of schizophrenia

It is argued that schizophrenia is passed on from one generation to the next through genetic inheritance, and so therefore a person who is closely related to someone with schizophrenia is more likely to develop the disorder

Polygenic

It is more likely that different combinations of genes make individuals more vulnerable to the disorder

Specific genes linked with schizophrenia

NRG3 gene, NRG1 and ERBB4 genes

Typical antipsychotic drugs

Eg Chlorpromazine, a dopamine antagonist that works to reduce the effects of dopamine by binding to dopamine receptors but not stimulating them, thus blocking their action

Atypical antipsychotic drugs

Eg clozapine and risperidone, newer types of drug treatments that temporarily blocking dopamine receptors before dissociating to allow normal transmission of dopamine. This reduces the positive symptoms of schizophrenia, and causes less extra-pyramidal side effects.

Tardive dyskinesia

An example of extrapyramidal side effects, which is characterised by involuntary chewing and sucking, jerky movements and twisting of the mouth and face, all of which can be permanent

Family dysfunction explanation

Claim that the risk of schizophrenia is increased when there are abnormal patterns of communication within the family

The double-bind hypothesis

Children can find themselves ‘trapped’ in situations where they fear doing the wrong thing, but are not given clear guidance on what ‘the wrong thing’ is. When they do ‘get it wrong’ the parent withdraws affection/love as a punishment. The child frequently receive contradictory messages from parents I.e. where a verbal message is given but opposite behaviour is exhibited.

Highly expressed emotion

Refers to the level of negative emotion expressed towards a patient bu their carers, including:

Verbal criticism of the patient

Hostility towards the patient

Emotional over-involvement in the life of the patient

Schisophenogenic mother

Schizophrenia causing, a mother who is cold, rejecting, controlling and tends to cause a family environment characterised by tension and secrecy

Metarepresentation

The cognitive ability to reflect on our own thoughts and behaviour. It is believed that a dysfunction contributes to the onset of hallucinations

Central control

The cognitive ability to suppress automatic responses while we perform deliberate actions instead. Disorganised speech and thought disorder could result from the inability to suppress automatic thoughts and speech triggered by other thoughts