Biological therapy for schizophrenia

Question 1

Most common treatment for schizophrenia

Answer 1

Antipsychotic drugs

Question 2

What does antipsychotics divide into?

Answer 2

Typical antipsychotics

Atypical antipsychotics

Question 3

Typical antipsychotics: Role of dopamine antagonists

Answer 3

Blocking dopamine receptors in the synapses in the brain, reducing the action of dopamine

Initially dopamine levels build up after taking chlorpromazine but then production is reduced

This normalises neurotransmission in key areas of the brain which in turn reduces symptoms like hallucinations

Question 4

Typical antipsychotics: Chlorpromazine

Answer 4

Also has an effect on histamine receptors which appears to lead to a sedation effect

Calm anxious patients when they are first admitted to hospital

Question 5

Comer (2000)

Answer 5

Typical antipsychotics reduce positive schizophrenic symptoms in the majority of patients and appear to be a more effective treatment for schizophrenia than any of the other treatments used alone

Question 6

How are typical antipsychotics taken?

Answer 6

As a tablet, syrup or 2 weekly injections

Syrup is absorbed faster
Administered daily
-> starting from a very low dose gradually increasing to a general maximum of 400-800mg (max 1000mg)

Question 7

Side affects of typical antipsychotics

Answer 7

• Dizziness
• Weight gain
• Itchy skin
• Blurred vision
• Sleepiness
• Agitation

Serious side effect = tardive dyskinesia (caused by dopamine super sensitivity, involuntary facial movement such as blinking, lip smacking e.t.c)

Question 8

Atypical antipsychotics: Clozapine

Answer 8

Clozapine binds to dopamine receptors as chlorpromazine does but also acts on serotonin and glutamate receptors

This drug was more effective than typical antipsychotics as clozapine reduces depression and anxiety as well as improving cognitive functioning

Also improves mood - important - up to 50% of people with schizophrenia attempt suicide

Question 9

Atypical antipsychotics: Risperidone

Answer 9

Developed in the 1990s because clozapine was involved in the deaths of some people from a blood condition called agranulocytosis

Risperidone like clozapine binds to dopamine and serotonin receptors

But risperidone binds more strongly to dopamine receptors and it is therefore more effective in smaller doses than most antipsychotics and has fewer side effects

Question 10

How are atypical antipsychotics taken?

Answer 10

Can be taken as a tablet, syrup or 2 weekly injections

Attempt to make a drug as effective as clozapine but without the risk of severe side effects

Smaller doses - initally very low, leading to daily doeses of 4-8mg (12mg max)

Question 11

Strength of biological therapies

Answer 11

Evidence of effectiveness:
- Thornley et al
- Metzler et al

Question 12

EVALUATION: Evidence of effectiveness

Answer 12

P-There is evidence that treating schizophrenia biologically works, which is one of its advantages.

E - Thornley et al. reviewed data from 13 trials involving 1,121 participants and discovered that when compared to a placebo, chlorpromazine was linked to improved functioning and a reduction in the severity of symptoms.

E - The advantages of atypical antipsychotics are also supported. Clozapine is more effective than typical antipsychotics, according to Metzler et al.’s conclusion, and it works in 30–50% of treatment-resistant cases.

L - So far as we can determine, antipsychotics are effective.

Question 13

COUNTERPOINT TO EVIDENCE OF EFFECTIVNESS

Answer 13

P - Most studies are of short term effects only and some data sets have been published several times, exaggerating the size of the evidence base (Healy 2012).

E - Also benefits may be due to calming effects of drugs rather than real effects on symptoms.

E - Powerful calming affect, make it easy to demonstrate that they have some positive effect on people experiencing symptoms of schizophrenia. This is not the same as saying they really reduce the severity of psychosis

L - This means the evidence of effectiveness is less impressive than it first appears

Question 14

Two limitations of biological therapies

Answer 14

The likelihood of side effects for antipsychotic drugs
We do not know why antipsychotics work

Question 15

EVALUATION: The likelihood of side effects for antipsychotic drugs

Answer 15

P - The possibility of side effects is one of the limitations of antipsychotic drugs.

E - Common side effects of antipsychotics include agitation, weight gain, and dizziness. Due to dopamine sensitivity, prolonged use might cause lip-smacking and grimacing (tardive dynkinesia).

E - The most dangerous side effect is neuroleptic malignant syndrome, which can be fatal since it disrupts the regulation of multiple body systems and occurs on by blocking dopamine action in the hypothalamus.

L-This indicates that people may avoid antipsychotics (limiting their effectiveness) and that they can have negative side effects in addition to positive ones.

Question 16

EVALUATION: We do not know why antipsychotics work

Answer 16

P - The fact that we don’t understand why antipsychotics operate is another drawback.

E - The dopamine hypothesis, which suggests that individuals with schizophrenia have higher-than-normal amounts of dopamine in their subcortex, is closely linked to the use of the majority of these drugs.

E - However, there’s evidence to suggest that this might not be the case and that dopamine levels in other brain regions may be too low as opposed to excessive. Then most antipsychotics shouldn’t be effective.

L - This suggests that antipsychotics might not be the best course of action; perhaps there is another reason for their apparent success.

Question 17

EVALUATION ExTrA: Chemical cosh

Answer 17

P - The use of antipsychotics poses a bit of a moral dilemma

E - They clam patients distressed by hallucinations and delusions and they allow patients to engage with other treatments

E - It is believed that antipsychotics have been used in hospital situations to calm people with schizophrenia and make them easier for staff to work with

However calming people distressed by hallucinations and delusions probably makes them feel better, and allows them to engage with other treatment (e.g CBT) and services

L - On balance then there are clear benefits to using antipsychotics to calm people with schizophrenia and in the absence of a better alternative they should probably be prescribed