Paper 3: Schizophrenia Flashcards
What are the positive symptoms of schizophrenia?
Hallucinations.
Delusions, beliefs not based in reality.
What are the negative symptoms of schizophrenia?
Avolition, lack of desire or motivation for anything.
Speech poverty reduction in the quality or amount of speech.
What are the two ways of diagnosing schizophrenia and whats the difference?
DSM-5 (the American guide to diagnose schizophrenia) and the ICD-10 (the World health Organisation’s guide). DSM-5 requires at least 1 positive symptom to be present while the ICD-10 requires only negative symptoms.
How reliable are schizophrenia diagnosis?
Beck et al found a 54% concordance rate with diagnosis between doctors.
Soderberg found an 81% concordance rate with the DSM-5 compared to Jakobsen with a 98% concordance rate with the ICD-10.
Strengths of the reliability Diagnosis of Schizophrenia?
Improvements in reliability over time, greater concordance rate in newer studies.
Weaknesses of the reliability diagnosis of schizophrenia?
Low reliability between the DSM-5 and the ICD-10, in general the DSM-5 is seen as more reliable due to its specific criteria.
Co-morbidity, people often suffer from depression alongside schizophrenia, often confusing the diagnosis.
Who studied the validity of the schizophrenia diagnosis?
Rosenhan, used 8 healthy volunteers and all were falsely admitted to hospital and diagnosed with schizophrenia. Took between 7-52 days to release them.
Strengths of the validity of schizophrenia diagnosis?
Although Rosenhan appears to make the diagnosis invalid, more recent studies suggest it has improved eg Mason et al.
Realistic gender difference in schizophrenia, Kulkarni et al found women’s estrogen can be responsible for the gender disparity in schizophrenia diagnosis.
Cultural differences, there is a valid disparity in schizophrenia diagnosis due to the higher rates of schizophrenia in Afro-Caribbean people.
Weaknesses of the validity of schizophrenia diagnosis?
Shares symptom overlap with other disorders eg speech poverty found in both schizophrenia and autism.
Gender differences, Cotton et al suggests the better interpersonal functioning of women may cause doctors to miss the symptoms of schizophrenia.
Cultural differences, there is an invalid disparity in diagnosis of Afro-Caribbean people due to over-diagnosis in Britain or under-diagnosis in the Caribbean.
What are the 3 factors in the biological explanations for schizophrenia?
These include genetics, neural (brain) abnormalities, and abnormalities in dopamine.
Who conducted schizophrenia twin studies and what were the results?
Gottesman found 48% concordance rate for schizophrenia in identical twins compared to non-identical.
Other studies include Tienari et al who found adopted children of a schizophrenic biological mother were more likely to have schizophrenia than a control group of adoptees.
Strengths of the genetic explanations for schizophrenia?
Supporting evidence: The familial and twin studies of schizophrenia above support the genetic explanation of schizophrenia because they show that being closely related (and thus having similar genes) to someone with schizophrenia increases the likelihood of suffering from schizophrenia.
Multiple genes: It is unlikely that there is a single gene responsible for schizophrenia. Instead, multiple genes likely combine to increase a person’s risk of developing schizophrenia. In a study of more than 36,000 schizophrenic patients, Ripke et al (2014) found 108 different genetic variations that were correlated with schizophrenia, supporting the existence of a genetic component to the disorder. Further, many of these genetic variations were related to dopamine transmission, so genetic explanations can be combined with the dopamine hypothesis to provide a holistic explanation of schizophrenia.
Weaknesses of the genetic explanation for schizophrenia?
Other factors: Although most studies suggest genetics play a part in the development of schizophrenia, it is clear that other factors are important too. If schizophrenia was 100% genetic, you would expect concordance rates between identical twins to be 100%. However, most studies find concordance rates among identical twins to be less than 50%, which suggests there is more to schizophrenia than just genetics. This suggests an interactionist approach is best for explaining schizophrenia.
Methodological issues surrounding twin studies: Twin studies typically assume that twins have identical upbringings and so any differences in concordance rates between identical and non-identical twins must be explained by genetics. However, environmental factors likely play a role too. For example, looking identical probably makes parents treat identical twins more similarly than they would non-identical twins. As such, greater similarities in environment could contribute to higher concordance rates for schizophrenia among identical twins, with the influence of genetics being exaggerated.
What are neural correlates?
Examinations of the brain comparing a normal brain to a schizophrenic brain.
What were 2 neural correlate studies conducted?
Johnson et al found enlarged ventricles in correlation to schizophrenia.
Li et al took a meta-analysis and found reduced activity during facial processing tasks.
Weaknesses of the neural correlate explanation?
Conflicting evidence: Although several studies have found correlations between enlarged ventricles and schizophrenia, there are many exceptions. There are many people with enlarged ventricles who do not have schizophrenia, and there are many people with schizophrenia who do not have enlarged ventricles.
Correlation vs. causation: Although there are correlations between schizophrenia and certain neural patterns, it can be difficult to determine whether abnormal brain functioning causes schizophrenia symptoms or whether it is an effect of schizophrenia. For example, does reduced activity in the bilateral amygdala of schizophrenic patients cause difficulties in emotional processing, or do schizophrenics’ reduced emotional processing (caused by some other factor) result in reduced blood flow and activity in the bilateral amygdala?
What is the neurotransmitter explanation for schizophrenia?
The Dopamine Hypothesis. Seeman et al and other studies reported a reduction in schizophrenic symptoms when on dopamine inhibitors.
What further evidence supports the Dopamine Hypothesis?
Curran et al found that drug that cause an increase in dopamine can be responsible for causing schizophrenia in non-schizophrenic people.
Post-mortum, Bird et al found greater dopamine concentration in schizophrenic brains than normal brains.