Drug treatment of schizophrenia

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Antipsychotic drugs

These are widley used to treat acute episodes of psychosis and prevent relapse

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Conventional antipsychotic drugs

  • Conventional antipsychotic drugs work by reducing the effects of dopamine and so reducing the symptoms of schizophrenia
  • They are known as dopamine antagonists as they bind to dopamine receptors but do not stimulate them, thus blocking their actions.
  • By reducing the stimulation of dopamine, antipsychotic drugs can eliminate positive symptoms such as hallucinations and delusions.
  • Chlorpromazine is a common conventional antipsychotic and was found to have therepeutic effects on agitated patients, and in particular, alleviated hallucinations and delusions. 
  • Anti-psychotic drugs are also reffered to as neuroleptics, and in double blind placebo trials of these drugs, they have been shown to have a specific impact on positive symtoms.
  • A small number of people, do not respond however (Loebel et al found 16% didn't)
  • The effectiveness of these antagonist drugs led to the development of the dopamine hypothesis
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Chlorpromazine

(http://www.schizophrenia.com/research/Slide17.jpg)

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Evaluation of conventional antipsychotic drugs

  • Highly effective at treating acute symptoms - the control of acute symptoms of schizophrenia (hallucinations and delusions) with neuroleptics has proven highly effective
  • Studies comparing antipsychotic medication with a placebo demonstrate the theraputic sucess of conventional antipsychotic drugs. Coie et al (1964) compared drug treatment with a control group, the drug group took Chloropromazine for 6 weeks, while the control group took a placebo (drug containing sugar only!) All of the patients improved on the antipsychotic drug, and 48% of patients on the placebo worsened. 75% of patients taking the antipsychotic drug had 'much improvement,' whilst this was only 25% when the patients took a placebo.
  • This shows conventional  antipsychotics at the very least prevent symptoms from getting worse. For many (75%) it dramatically improves symptoms.
  • However, drug treatment is not effective for all schizophrenics, a small number fail to respond to these drugs, and Lobel et al found, in 1992, that 16% failed to recover within 12 months of the first treatment. These may need alternative drugs or combined therapies.
  • The drugs are also not effective in treating negative symptoms, and only work on positive symptoms such as hallucinations. A new drug is therefore needed for the negative symptoms
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Appropriateness of conventional antipsychotics

  • Drug treatment is used to control symptoms, it is not a cure. These drugs must be taken regularly (even  if no positive symptoms are currently being experienced) otherwise they can return, often with great severity.
  • Conventional antipsychotics have many worrying side effects which can be quite distressing and include; parkinsonism, which includes a tremor and shuffling gait and Tardive Dyskinasea, which are involuntary movements of the head and tounge, and 30% of people taking this medication develop this condition, and it is irreversible in 75% of cases (Hill, 1986.)
  • People may therefore stop taking the drug, due to these side effects, or their physical sympoms may lower their self esteem
  • Ross and Read (2004) also argue that being perscribed medication reinforces the view that there is something wrong with you. This prevents the individual from thinking about possible stressors (such as life history or current circumstances) that may trigger the disorder. In turn, this reduces their motivation to look for possible solutions that may alleviate these stressors and, in effect, reduce their suffering.
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Atypical antipsychotic drugs

  • Atypical antipsychotic drugs (eg, Clozapine and Risperdone) are new-generation drugs. They also act on the dopamine system by reducing levels but are also thought to block serotonin receptors in the brain too.
  • They are reffered to as 'atypical' neuroleptics
  • Such drugs have proved effective for those who don't respond to the older neuroleptics. These newer drus also do not have side effects as normal ones do, apart from the occasional reporting of akathisia (extreme restlessness and agitation.)
  • These work by temporarily occupying the receptors and then rapidly detaching to allow normal dopamine flow, It is this characteristics in these atypical drugs that psychologists believe are responsible for the lower side effects, such as Tardive Dyskinasea, found in these drugs when compared to conventional antipsychotics. This could be because a minimal amount of dopamine must be required for voulantary relaxed muscle friction
  • Clozpine has also proved effective in cases where traditional neuroleptics have failed to shift all symptoms of psychosis, studies show up to 66% of patients with stubborn symptoms do respond within 12 months (Meltzer, 1999.)
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Evaluation of atypical antipsychotic drugs

  • Research evidence suggests the benefits over conventional antipsychotic drugs. Meltzer (1999) found that up to 66% of schizophrenics with stubborn symptoms, resistant to conventional antyipsychotics, did respond within 12 months Clozapine treatment.
  • However, a meta-analysis of studies published in 1999 revealed that the superiority of these drugs compared to conventional drugs was only moderate (Leuch et al 1999.) 
  • Effectiveness with negative symptoms - The claim that atypical antipsychotics are particularly effective with negative symptoms has only marginal support. In Leucht's met analysis, two of the atypical drugs were 'slightly' more effective than conventional, one was 'as effective' and one 'slightly worse.'
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Appropriateness of atypical antipsychotics

  • They may lower the risk of Tardive Dykinasea, but do have their own problems such as nausea, weight gain, irregular heartbeat and excessive salivation.
  • They may ultimately be more appropriate in the treatment of schizophrenia, a they do have fewer side effects, which, in turn means the patient is more likely to continue with their medication, and will therefore see more benefits.
  • They are, however, potentially life threatening. A minority of patients have developed a possible life threatening disorder in which levels of white blood cells drop dramatically. This requires regular blood monitoring.
  • Newer drugs (such as Risperidone) are very expensive and so are not widely used.
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Evaluation of antipsychotic drug treatment

  • Drastically reduces positive symptoms, and allows patients to live a normal life in the community.
  • However, they just relieve symptoms and don't cure schizophrenia. 
  • If the patient stops taking the drug, the symptoms return
  • There are unpleasant side effects to some drugs
  • Overall, these drugs are an indispensible part of the treatment of schizphrenia and will continue to be the primary treatment of schizophrenia until a better drug is found. 
  • We do need to know why some patients do not improve during drug therapy.
  • Medication is best at continual low dosage to control relapse rates, but these drugs only extend the interval beween relapses, they do not prevent them.
  • The neuroleptics can be taken through bimonthly injections, which ensures that the patient is taking the drugs, but these drugs are a mean of controlling, not curing psychosis.
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Evaluation of drug treatment

  • The side effects of neuroleptic meds are distressing, eg, muscular spasms, parkinsonism and tardive dyskinseia.
  • Clozapine is associated with the potentially fatal lowering of white blood count, and it's use reuqires regular blood monitioring. Other side effects of this include sedation, hyper salivation and weight gain.
  • The newer drugs, such as Risperidone don't lead to the distressing side effects found in early ones, but these drugs are very expensive and so aren't widely used.
  • Neuroleptic meds is best at continual low dosage to control relapse rates, but these drugs only extend the interval between relapses - they don't prevent them.
  • The neuroleptcis have become popular as bimonthly injections, which ensure adherence to regimes and help prevent relapse. However, these drugs are a means of controlling, not curing, psychosis.
  • There is no evidence that neurolpetics are effective for negative symptoms.
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