Schizophrenia Flashcards
What percentage of the population does schizophrenia affect?
affects 1% of population and mainly in men
What is the classification of a mental disorder?
the process of organising symptoms into categories based on symptoms frequently experienced together
What are the two systems to classify a mental disorder?
DSM-5 and ICD-10
What is the DSM-5 ?
DSM-5 - one positive symptom is enough for diagnosis
- american system,
- continuous signs of disturbance for 6 months
What is the ICD-10?
ICD-10 - two negative symptoms are enough for diagnosis -international system
-continuous signs of disturbance for 1 month
What are the positive symptoms of schizophrenia?
additional symptoms beyond those of ordinary existence e.g hallucinations and delusions
What are hallucinations?
auditory and visual sensations of something that is not really there
What are delusions?
known as paranoia and are irrational beliefs
What are the negative symptoms of schizophrenia?
loss of usual abilities and experiences e.g speech poverty and avolition
What is speech poverty?
reduction in quantity and quality of speech e.g changing topic mid sentence
What is avolition?
loss of motivation e.g poor hygiene
What are the issues in diagnosis?
Good reliability, co-morbidity, cultural bias, gender bias, symptom overlap
Why is there good reliability in the diagnosis of schizophrenia?
Rosenhan’s study, was not valid but ‘patients’ were consistently diagnosed wrong.
7 confederates said that they could hear a voice saying ‘thud, hollow, empty’ which was not a symptom of schizophrenia. 12 hospitals in 5 different states were used + all were admitted to hospital with no confederates being detected.
What is comorbidity? + the percentage rates of schizophrenia being diagnosed with another disorder?
this is the extent to which 2+ conditions occur together (questions the validity of classifying the 2 conditions separately)
-50% depression, 47% substance abuse, and 29% PTSD
Why is there cultural bias in the diagnosis of schizophrenia?
African-Americans + Afro-Caribbeans are 9 times more likely to be diagnosed due to over-interpretation of positive symptoms, which may be more acceptable elsewhere (hearing voices, being overly emotional)
Why is there gender bias in the diagnosis of schizophrenia?
accuracy of diagnosis is gender dependent, women are less likely to be diagnosed due to having closer relationships thus they get support (mask symptoms) but men do not hence women with schizophrenia often function better than men.
What is symptom overlap?
2+ conditions share symptoms
What are the biological explanations for schizophrenia?
family studies + candidate genes + mutations
What are family studies?
risk of schizophrenia increases with genetic similarity with a relative with the disorder e.g 48% risk with identical twin, 17% risk with non-identical, 9% risk with siblings, 6% risk with parents however is only correlational
What are candidate genes?
many different genes involved with schizophrenia (polygenic), different combinations of factors can lead to disorder
What occurs in a mutation?
mutation in parental dna caused by radiation, poison, viral infection
What is Gottesman’s family study ?
Gottesman (1991) found that children with 2 schizophrenic parents = 46% concordance, 1 schizophrenic parent = 13% and sibling = 9%
What is Joseph’s twin study?
(Joseph 2004) - MZ’s 40% and DZ’s 7%, MZ’s always higher and the difference between them suggests that schizophrenia is inherited/has a genetic component because MZ’s share 100% of their genes
What is Tienai’s adoption study?
(Tienai 2000) - biological mother had schizophrenia, 7% of adopted children did compared to 2% of controls hence child is just as likely to have schizophrenia even if not with biological mother (passed on through genetics)
What evidence is there for schizophrenia being influenced by the environment?
genetically DZ’s are the same as ordinary siblings (share 50% genes), thus the rates should be the same but it was found that DZ’s rates were higher (17%) than sibling rates (9%), this suggests that schizophrenia can be influenced by the environment.
What is the dopamine hypothesis?
dopamine is a neural correlate of schizophrenia, antipsychotics used to treat parkinson’s disease (associated with low DA levels) thus schizophrenia may be associated with high DA levels, particularly positive symptoms.
What results in hallucinations and delusions?
Messages from neurones that transmit dopamine fire too easily/often thus schizophrenics have too many D2 receptors on post synaptic neurones so more dopamine binds and more neurones are fired → leading to hallucinations and delusions.
