1950s chlorpromazine acts as a antagonist to DA as it blocks the receptors which reduces the uptake of DA. can be taken daily up tp 1000mg. atfirst causes a increased level due to build up but gradually reduces the production. can reduce symptoms like hallucinations. supports the DA hypothesis. also used as a sedative on histamine receptors. calm patients
1970s minimises the side effects but increasing/maintaining the effectiveness
clozapine= stopped in 1970s due to death caused by a blood condition called agranulocytosis. introduced again 1980 with patients taking regular blood tests, more effective, due to side effects not available as a injection 450mg max. binds to DA and serotonin receptors and glutamate helps reduce mood and depression. good for schizo suffers with depression also
risperidone= 1990, wanted to be as effective as clozapine but without side effects 12mg max, binds to DA and serotonin receptors but binds stronger to DA than clozapine so effective in smaller doses.
Thornley- compared effects of chlorpromazine and a placebo. data from 13 trials showed the chlorpromazine is associated with better functioning and reduced symptoms. and also reduced the relapse rate.
also clozapine has been used in treatment resistant cases, 50%
BUT studies in comparing clozapine and risperidone have been inconclusive
typical- side effects include dizziness, stiff jaw and weight gain, long term, tardive dyskinesia caused by DA sensitivity- lip smacking and facial movements.
most serious is neuroleptic malignant syndrome caused by the drug blocking action in the hypothalamus. which control bodily functions, causes high temp and comas.
clozapine- could cause blood condition so needs regular blood tests
A03: use of antipsychotics depends on DA hypothesis
clear DA levels are to high in the sub cortex of the brain, due to DA hypothesis. but, there are low levels in other areas of the brain eg, prefrontal cortex. so antipsychotic drugs cannot only lower DA levels as this would make negative symptoms worse. therfore the way they work is unclear reducing validity.