Schizophrenia Flashcards
What are the two systems to classify schizo with?
- DSM-5 = means that one positive symptom must be present.
- ICD-10 = two or more negative symptoms are sufficient for a diagnosis.
What are the positive symptoms of schizo and what is the definition of one?
POSITIVE SYMPTOM = additional experiences beyond those of ordinary existence.
- Hallucination = sensory experiences that have no basis in reality or distorted perceptions of real things. eg hearing voices or seeing people who aren’t there.
- Delusions = beliefs that have no basis in reality - make a person with schizo behave in ways that make sense to them but strange for others. eg belief about being super important(delusions of grandeur.)
What are the negative symptoms of schizo and what is the definition of one?
NEGATIVE SYMPTOM = loss of usual abilities and experiences.
- Avolition = severe loss of motivation to carry out everyday tasks. This results in lowered activity and unwillingness to carry out goal-directed behaviour.
- Speech poverty = a reduction in the amount and quality of speech. can include a delay in verbal responses during a conversation.
What are the issues in diagnosis? Included definitions of reliability and validity.
- RELIABILITY = the extent to which the diagnosis of schizo is consistent.
- VALIDITY = the extent to which the diagnosis and classification techniques measure what they are designed to measure, in this case, schizo.
1. CO-MORBIDITY = occurrence of two illnesses together which confuses diagnosis and treatment.
2. SYMPTOM OVERLAP = when two or more conditions share the same symptoms, questioning the validity of classification.
3. GENDER BIAS.
4. CULTURA BIAS.
Evaluation of the diagnosis of schizo.
- low reliability = Cheniaux had twp psychiatrists independently diagnose 100 patients using the DSM-5 and ICD-10 criteria. Inter-rater reliability was poor. one diagnosed 26 schizos using DSM and 44 with ICD. second diagnosed 13 with DSM and 24 with ICD.
- Cheniaux proved it lacked validity - much more likely to be diagnosed using ICD than DSM.
- Co-morbidity - Buckley found that around half of patients with a diagnosis of schizo also had a diagnosis of depression (50%) and substance abuse(47%).
- Gender bias - Longenecker reviewed of schizo and found that since the 1980s, men more diagnosed than women. Cotton also found that women function better than men with schizo, so they could be underdiagnosed for this reason.
- Cultural bias - African Americans are more likely to be diagnosed with schizo because some behaviours classed as positive symptoms are normal in these cultures eg hearing voices of an ancestor.
Biological explanations for schizo - explain the genetic basis.
- schizo runs in families - Gottesman did a family study and found that MZ twins have a 17% shared risk and DZ twins have a 17% shared risk. Siblings had 9%. Thus there is a strong genetic relationship between genetic similarity of family members and the likelihood of developing schizo.
- There is also evidence of candidate genes that either schizo is polygenetic ( each gene confers a small increased risk for schizo) or it is heterogeneous (different combinations lead to schizo). Ripke studied 37,000 patients and found 108 separate genetic variations associated with an increased risk.
Biological explanations for schizo - explain the dopamine hypothesis.
Dopamine is widely believed to be involved in schizo because it is featured in the functioning of brain systems related to the symptoms of schizo.
HIGH DOPAMINE = high dopamine in the subcortex is associated with hallucinations and poverty of speech.
LOW DOPAMINE = low levels in the prefrontal cortex is associated with decision making.
Biological explanations for schizo - explain neural correlates.
Neural correlates are measurements of the structure and function of the brain that correlates with positive or negative symptoms of schizo.
Avolition may be explained by low levels in the ventral striatum. - Juckel found this negative correlation.
Allen found that patients experiencing auditory hallucinations recorded lower levels in the superior temporal gyrus.
Evaluation of the biological explanations for schizo.
+ strong evidence for genetic vulnerability - Tienari showed that children of people with schizo are still at a heightened risk of schizo even if adopted into a family with a history of schizo. - it may not be entirely genetic, but there is overwhelming evidence that genetic factors make people vulnerable.
+ Antipsychotic drugs that lower dopamine have been effective in reducing symptoms.
– however some candidate genes also code for glutamate, so dopamine does not provide a complete explanation for schizo.
– correlation does not always mean causation - a negative correlation may suggest that low activity in ventral striatum causes avolition, but what if avolition causes less info to be passed through the ventral striatum which causes low activity.
Psychological explanations for schizo - family dysfunction - explain the theory of schizophrenogenic mothers.
Fromm-Reichmann psychodynamic explanation based patients early experiences on mothers who cause schizo.
These mothers are cold, rejecting and controlling and create a family climate of tension and secrecy. This leads to distrust and paranoid delusions and schizo.
Psychological explanations for schizo - family dysfunction - explain the double-bind theory.
Bateson described how a child may be regularly trapped in situations where they fear doing the wrong thing but receive conflicting messages about what counts as wrong.
They cannot express the unfairness of the situation.
The child is punished, if the get something wrong(often), through the withdrawal of love.
They learn that the world is confusing and dangerous which leads to disorgansied thinking and delusuions.
Psychological explanations for schizo - family dysfunction - explain the theory of expressed emotion.
Expressed emotion is the level of emotion (mainly negative) expressed towards the schizo patient. This includes:
- verbal criticism of the patient.
- hostility towards them.
- emotional over-involvement in their life.
High levels of EE causes stress in the patient, a primary explanation for relapse in patients with schizo.
Psychological explanations for schizo - cognitive explanations - explanation.
DYSFUNCTIONAL THOUGHT PROCESSING - lower levels of information processing in some areas of the brain suggest cognition is impaired. - reduced levels in ventral striatum = negative symptoms.
METAREPRESENTATION - is the cognitive ability to relfect on thoughts and behaviours (Frith.) - this dysfunction disrupts our ability to recognise our own thoughts as our own. - leads to hearing voices and delusions.
DYSFUNCTION OF CENTRAL CONTROL - Frith identified this as an explanation for speech poverty. Central control refers to the cognitive ability to suppress automatic responses while doing something else. - People with schizo experince derailment of thoughts and spoken sentences because eac word triggers automatic associations they cannot suppress.
Evaluation of psychological explantions for schizo.
– evidence for family relationships is often retrospective - Read reviewed 46 studies and concluded 69% of all female patients with schizo and 59% of men had a history of sexual abuse in childhood. - however, this evidence was gathered in retrospect and they may have distorted views of childhood due to the schizo.
+ support for info processing - Stirling compared 30 schizo with 18 non schizo with cognitive tasks. Patients took twice as long to surpress the impulse to read the word and not the colour. - supports Frith.
– Majorly reductionist as it does not consider the biological approach and how the diathesis stress model proves the schizo is a mixture of both factors.
Biological therapies for schizo - drug therapy. Explain typical antipsychotics.
TYPICAL - they work by trying to reduce the action of dopamine - strongly associated with the dopamine hypothesis.
Dopamine antagonists work by blocking dopamine receptors in the synapses of the brain - reducing action of dopamine.
Chlorpromazine is an example.
