Download Typical Antipsychotics - Effectiveness - School

Schizophrenia – Biological
Therapies 2
Drug Therapy (chemotherapy)
Typical Antipsychotics
Eg. Chlorpromazine
For this subtopic:
 We need to distinguish between the
positive and negative symptoms of
schizophrenia
the positive symptoms include delusions and
hallucinations
 the negative symptoms include lack of
motivation, lack of emotion, social withdrawal
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AO1: Typical Antipsychotics
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Known as Neuroleptic Drugs
Developed in 1950s, originally used to slow
metabolism during surgery
Examples: Chlorpromazine and Haldol
Block activity of Dopamine (DA) by occupying
active sites in D2 receptor neurones – prevents
impulse from crossing synapse
Usually administered orally but can be deepmuscle injected for slow release, useful for nonvoluntary cases
AO1: Atypical Antipsychotics
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Developed more recently in the second wave of
antipsychotic meds, introduced in 1970s
More recent and thus more expensive
Examples: Clozapine and Olanzapine
Also reduces DA activity but thought to target
different DA receptors (eg. D1,D4), and dissociates
more quickly creating less of a block at the
synapse
Some research has indicated that it also targets
serotonin receptors, though others disagree
Typical Antipsychotics - Effectiveness
Effectiveness is greater in reducing
positive symptoms than negative ones
 More effective treatment for S than any of
the other approaches used alone (Comer,
2001)
 Most beneficial within the first 6 months
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Typical Antipsychotics - Effectiveness
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Sampath (1992) studied patients with S who
had been taking neuroleptic drugs for 5 years
One group then switched to a placebo (an
inactive substance), whereas the other group
continued to take the drug
 In the placebo group, 75% of the patients
relapsed within 1 year, compared with 33% of
patients who continued to receive the drug
 Shows that these drugs are effective at keeping
symptoms of S at bay but study is correlational so
can’t infer causality.
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Typical Antipsychotics - Effectiveness
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Another study showing it works
Atypical Antipsychotics - Effectiveness
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Seem to have an beneficial effect on both positive and
negative symptoms. Some research suggests this is
because it targets serotonin receptors as well as DA
ones
Fewer side effects than neuroleptic drugs, eg. less likely
to causing extrapyramidal motor control disabilities in
patients (that can persist even after treatment has
ended)
Benefit 85% of patients compared to 65% for
neuroleptics (Voruganti, 1999)
Meltzer (1999) found that about one-third of patients
who had shown no improvement with neuroleptic drugs
responded well to clozapine
Typical vs. Atypical
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Mustn’t be too quick to say atypical are better than typical
– this is a reductionist approach
Using a number of parameters to assess quality of life,
NHS researchers found typical anti-psychotics were no
worse than atypical anti-psychotics (Jones, 2006)
Because each medication (whether typical or atypical) has
its own profile of desirable and adverse effects, the doctor
may recommend one of the older ("typical" or first
generation) or newer ("atypical" or second generation)
antipsychotics alone or in combination with other
medications, based on the symptom profile, response
pattern, and adverse effects history of the individual
patient.
Antipsychotics - Appropriateness
How are these drugs Appropriate?
 Lots of evidence that S results from
abnormality in DA system, so a solution that
targets this seems appropriate
 In some cases drug therapy is a quick and
painless way to manage symptoms
 BUT we are not entirely sure how they work so
some question their appropriateness for this
reason
Typical Antipsychotics - Appropriateness
How are these drugs Inappropriate?
 Chlorpromazine side effects:
 Grogginess, visual problems, insomnia, sexual
dysfunction (Windgassen, 1992).
 AO3: many of these side FX reported in a hospital
setting – would it be same for those living in the
community?
 Big side effect: Tardive Dyskinesia - muscle
spasms etc in mouth & throat, leads to speech
probs & in extreme cases breathing difficulties
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Affects ~30% of those taking Chlorpromazine within 5
years, and is permanent in about 75% of these cases
Atypical Antipsychotics - Appropriateness
How are these drugs Inappropriate?
 Clozapine side effects:
Increased risk of developing diabetes or obesity
compared to Chlorpromazine
 Big side effect: Agranulocytosis, a disorder of the
bone marrow affecting 1-2% of takers
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Reduces white blood cell count and leads to reduced
immune system performance