biological therapy for schizophrenia

• antipsychotics?

  drugs used to reduce the intensity of symptoms in particular the positive symptoms on psychotic disorders like schizophrenia.
• typical antipsychotics?

  first generation of drugs for schizophrenia and other psychotic disorders, having been used since the 1950s. they work as dopamine antagonists and include chlorpormazine.
• atypical antipsychotics?

  drugs for schizophrenia developed after typical antipsychotics. target a range of neurotransmitters such as dopamine, serotonin. e.g. include clozapine and risperidone.
• clozapine?

  -developed in 1960s

  -more effective than typical antipsychotics

  not available as an injection due to potential fatal side effects

  -daily dosage typically 300 to 450mg a day.

  -binds to dopamine, serotonin and glutamate receptors. helps improve mood and reduces depression and anxiety and improves cognitive functioning
• risperidone?

  -recently developed, since the 1990s

  -developed in an attempt to be as effective as clozapine but with less serious side effects

  -can be taken in form of tablets, syrup or injections and lasts 2 weeks.

  -small dose first given then built up to dose of 4-8mg

  -binds to dopamine and serotonin receptors.

  -fewer side effects as it binds more strongly to dopamine than clozapine
• strength of antipsychotics?

  P - evidence to support its effectiveness

  E - evidence supporting antipsychotics are effective in tackling symptoms. thornley et al reviewed studies comparing the effects of chlorpromazine to control conditions. data from 13 trials with a total of 1121 participants showed that chlorpromazine was associated wit better overall functioning and reduced symptom severity as compared to placebo. evidence for benefits of atypical antipsychotics. meltzer concluded that clozapine is more effective than typical antipsychotics and other atypical antipsychotics and that its effective in 30-50% of treatment resistant cases where typical antipsychotics have failed.

  L - proves antipsychotics work
• CA for strength of antipsychotics?

  P - Healy suggested serious flaws with evidence for effectiveness.

  E - most studies are of short term effects only and some successful trials have had their data published multiple times exaggerating the size of the evidence base for positive effects. as antipsychotics have powerful calming effects its easy to demonstrate that they have some positive effect on people experiencing the symptoms of schizophrenia. its not the same as saying they really reduce the severity of psychosis.

  L - evidence base for antipsychotic effectiveness is less impressive than it first appears.
• limitation of antipsychotic drugs?

  P - likelihood of side effects

  E - typical antipsychotics are associated with a range of side effects including dizziness, agitation and sleepiness. long term use can result in tardive dyskinesia which is caused by dopamine supersensitivity and causes involuntary facial movements like grimacing, blinking and lip smacking. most serious side effect of antipsychotics is neuroleptic malignant syndrome which is caused when drug blocks dopamine action in hypothalamus, which is associated with regulation of a number of body systems. NMS results in high temperature, delirium and coma and can be fatal.

  L - antipsychotics can do harm as well as good and individuals who experience these may avoid such treatments.
• another limitation of antipsychotics?

  P - don't know why they work

  E - our understanding of the mechanism by which antipsychotic drugs work is strongly tied up with the original dopamine hypothesis. however we know that the original hypothesis isn't a complete explanation for SZ and in fact dopamine levels in other parts of brain are too low rather than too high. if this is true then most antipsychotics shouldn't work. adds to them being ineffective.

  L - antipsychotics may not be the best treatment to opt for maybe some other factors involve din their success.
• chlorpromazine?

  -since the 1950s

  -can be taken as tablets, syrup or by injection.

  -if taken orally, administered daily up to a maximum of 1000 mg, although initially doses are much smaller and for most people the dosage is gradually increased to a maximum of 400 to 800 mg.

  -Typical prescribed doses have declined over the last 50 years
• Dopamine antagonists ?

  -chlorpromazine works by acting as antagonists in the dopamine system.

  -Dopamine antagonists work by blocking dopamine receptors in the synapses of the brain, reducing action of dopamine.

  -Initially when an individual begins taking chlorpromazine dopamine levels build up, but then its production is reduced.

  -According to the dopamine hypothesis of schizophrenia this dopamine-antagonist effect normalises neurotransmission in key areas of the brain, reducing symptoms like hallucinations.
• Sedation effect ?

  -chlorpromazine is an effective sedative. believed to be related to its effect on histamine receptors but it's not fully understood how this leads to sedation.

  -Chlorpromazine often used to calm individuals not only with SZ but other conditions. often been done when patients are first admitted to hospitals and are very anxious.

  -Syrup is absorbed faster than tablets so it tends to be given when chlorpromazine is used for its sedative properties.