Theories of schizophrenia Flashcards
What are the positive symptoms of schizophrenia?
> Delusions
Hallucinations
Disorganised speech
Disorganised or catatonic behaviour
What are the negative symptoms of schizophrenia?
> Social withdrawal
Flat emotional response
Anhedonia
Lack of motivation
What did Tseng et al (2009) postulate?
The Neonatal ventral hippocampal lesion (NVHL) model of schizophrenia
What does the NVHL model of schizophrenia propose?
That during the second or third trimester a foetus develops hippocampal lesions. These then manifest as schizophrenia during late puberty
What was Largactil?
The first prescription psychiatric drug. It was used to treat schizophrenia
What did Carlsson and Lindqvist (1963) postulate?
The dopamine hypothesis of schizophrenia
What is the dopamine hypothesis of schizophrenia?
Schizophrenia is caused by an increased release of dopamine
How did Carlsson and Lindqvist support the dopamine hypothesis of schizophrenia?
They looked at the effect of amphetamine:
> In humans, can produce psychosis
> In experimental animals, stereotypies can be blocked by antipsychotics
> In non-medicated schizophrenics, amphetamine challenge results in greater dopamine release
What does the neurodevelopmental model of schizophrenia propose?
Between the prefrontal cortex and the ventral tegmental area there is a feedback mechanism (the mesocortical pathway). It is propsed that in schizophrenics this pathway is missing, leading to dopamine buildup in the prefrontal cortex
What does the neurodevelopmental model of schizophrenia propose?
Between the prefrontal cortex and the ventral tegmental area there is a feedback mechanism (the mesocortical pathway). It is propsed that in schizophrenics this pathway is missing, leading to dopamine buildup in the prefrontal cortex (hyperfrontality)
What evidence is there for hyperfrontality in schizophrenia?
Grilly (2002), schizophrenics treated with antipsychotics display motor disorders, suggesting normal dopamine levels in the temporal and parietal lobes
What are the side effects related to dopamine receptorantagonism?
> Parkinsonism
Tardive dyskinesia
Neuroendocrine effects
What is clozapine?
An antipsychotic with:
> A good therapeutic and side effect profile
> An affinity for multiple receptors
> A lower affinity for the D2 receptor
What is clozapine?
An antipsychotic with:
> A good therapeutic and side effect profile
> An affinity for multiple receptors
> A lower affinity for the D2 receptor
What is glutamate theory?
Schizophrenia is caused by NMDA receptor hypofunction
