Biological explanations for schizophrenia Flashcards
What had been found about schizophrenia in families?
Studies have shown that there is a genetic basis and that it runs in families. Gottesman found that the risk of developing schizophrenia if a parent has it is 6% and if your identical twin has it, you have a 48% chance of developing schizophrenia.
What research was carried out looking at candidate genes?
Individual genes are believe to be associated with inheritance and there are a number of genes which increase the risk of schizophrenia. Ripke compared 37000 patients genetic make-up to 113000 controls and found 108 genetic variations that increased the risk.
What does the dopamine hypothesis say about hyperdopaminergia?
High levels of dopamine in the subcortex, for example in the Broca’s area, may be associated with speech poverty and auditory hallucinations.
What does the dopamine hypothesis say about hypodopaminergia?
Low levels of dopamine in the prefrontal cortex are associated with negative symptoms of schizophrenia.
What are the neural correlates of negative symptoms?
Abnormal activity in the ventral striatum may be associated with avolition as it is involved in the nticipation of reward. Furthermore, a negative correlation was observed between the activity levels in the ventral striatum and the overall severity of negative symptoms.
What are the neural correlates of positive symptoms?
Brain scans of patients experiencing hallucinations showed lower activity levels in the superior temporal gyrus and anterior cingulate gyrus than the control group.
What are the strengths of biological explanations of schizophrenia?
Evidence for genetic susceptibility-Adoption studies show that children of schizophrenics are still more likely to develop schizophrenia and the evidence from Gottesman further supports this.
What are the weaknesses of the biological explanation of schizophrenia?
Mixed evidence for dopamine hypothesis-Evidence for antipsychotics use supports the hypothesis but it ignores the role of other neurotransmitters such as glutamate, which has been shown to be important in the development of schizophrenia.
Correlation causation problem-does the unusual brain activity cause the symptoms, are the symptoms causing unusual brain activity or is there another factor causing them both.
Role of mutation-If there is no family history, a mutation may cause schizophrenia and a positive correlation has been found between paternal age and schizophrenia.
Role of environment-Environmental factors are present but their role is unclear.
