Schizophrenia Flashcards
Classification - DSM-V - Requirements for Diagnosis
-Two symptoms - one specified positive symptom (delusions, hallucinations or speech disorganisation)
-Used in USA.
Classification - ICD 11 - Requirements for Diagnosis
-Two symptoms - one specified positive symptom.
-Used in Europe.
Positive Symptoms
-Symptoms that appear that reflect an excess or distortion of normal functions.
-Includes hallucinations, delusions, disorganised speech
Negative symptoms
-Symptoms that appear that reflect a diminution or loss of normal functioning.
-Includes speech poverty, avolition - a reduction of interests and desires as well as an inability to initiate and persist.
Reliability
-refers to the extent to which diagnoses are consistent - we would expect any measurement to produce the same data if taken on successive occasions.
Validity
-refers to the extent to which methods used to diagnose mental illnesses are accurate.
System Overlap
-refers to the fact that symptoms of a disorder may not be unique to that disorder but may also be found in other disorders, making accurate diagnosis difficult.
Co-morbidity
-refers to the extent that two conditions or diseases occur simultaneously in a patient, e.g. sz
Genetic Factors - Family Studies
-& E.g.
-Have established that schizophrenia is more common among biological relatives of a person with schizophrenia, and that the closer the degree of genetic relatedness, the greater the risk.
-E.g. Gottesman’s study, children with two schizophrenic parents had a concordance rate of 46% children with one schizophrenic parent a rate of 13%, and siblings a concordance rate of 9%.
Genetic Factors - Twin Studies
-& E.g.
-If MZ twins (genetically identical) are more concordant than DZ twins, this suggests that the greater similarity is due to genetic factors.
-E.g. Joseph (2004) calculated that the pooled data for all schizophrenia twin studies carried out prior to 2001 showed a concordance rate for MZ twins of 40% and 7% for DZ twins.
Genetic Factors - Adoption Studies
-& E.g.
-Helps disentangling genetic and environmental for individuals who share genes and environment.
-E.g. Tienari et al (2000) Finland of 164 adoptees whose biological mothers had been diagnosed with schizophrenia, 7% also received a diagnosis, compared to 2% in a controlled group of adoptees with no genetic history of schizophrenia.
Neural Correlates
-Changes in neuronal events and mechanisms that result in the characteristic symptoms of a behaviour/mental disorder.
Neural Correlates - Original Dopamine Hypothesis
-Explored hyperdopaminergia (excess of dopamine) as a cause for sz onset.
-High levels of D2 receptors means more dopamine binds and more neurone firing.
-These neurons play a key role in guiding a person’s attention, perception and thought - which are all affected by sz.
Neural Correlates - Revised Dopamine Hypothesis
-The newer version of the dopamine hypothesis poses the idea that hypodopaminergia in the prefrontal cortex may be responsible for the onset of negative symptoms.
-As well as stating that high levels of dopaminergic activity in the subcortical areas may be responsible for the onset of positive symptoms.
Family Dysfunction-Double Bind Theory
- Bateson et al suggested children who frequently receive contradictory messages from their parents are more likely to develop schizophrenia.
-E.g. If a mother tells her son that she loves him, yet at the same time turns her head away in disgust, the child receives two conflicting messages about their relationship.
Family Dysfunction -Schizophrenogenic Mother
-Reichmann proposed a type of parent that is ‘schizophrenia causing’.
-This parent is cold, rejecting, controlling, creates a family climate that is full of tensions and leads to paranoid delusions.
Family Dysfunction- Expressed Emotion
-A negative emotional climate associated with the onset of schizophrenia created by negative expression towards the sz person.
-Includes verbal criticism, hostility, anger and emotional over involvement.
Metarepresentation
-Cognitive ability to reflect on thoughts and behaviour.
Cognitive Explanations - Metarepresentation
-Frith et al stated dysfunction in metarepresentation would disrupt our ability to recognise our own actions and thoughts as being carried out by ourselves rather than someone else.
Cognitive Explanations - Central Control
-Speech poverty & thought disorder could result from inabilities to suppress automatic thoughts/speech.
-SZ’s tend to experience derailment of thought as each word triggers associations.
Drug Therapy - Typical Antipsychotics
-Reduces the effects of dopamine and so reduces the symptoms of schizophrenia.
-Typical antipsychotics are dopamine antagonists as they bind to but do not stimulate dopamine receptors, blocking their action.
-E.g. Chlorpromazine
Drug Therapy - Atypical Antipsychotics
-Carry a lower risk of extrapyramidal side effects - have a beneficial effect on negative symptoms.
-Also act on dopamine by blocking D2 receptors however only temporarily occupy them then rapidly dissociate to allow normal transmission.
-E.g. Clozapine & Risperidone
Cognitive Behavioural Therapy
-Used to help the patient identify and correct faulty interpretations caused by SZ.
-NICE recommends at least 16 sessions, which will help people to establish links between their thoughts, feelings, behaviours etc.
-In these sessions, patients are encouraged to trace the origins of their symptoms, they are encouraged to evaluate the content of their delusions.
-E.g. The ABC Model - Patient gives their explanation of the activating events, which are then rationalised and disputed by the therapist.
Family Therapy
-Name given to a range of interventions aimed at the family.
-Offered for a period of between 3 - 12 months and at least ten sessions - aims to reduce the level of expressed emotion.
-Garety et al found that individuals who receive family therapy only have a relapse rate of 25% compared to 50% for those who receive standard alone care.
