Drug therapy

Question 1

Antipsychotics

Answer 1

Drugs used to treat psychosis that usually target positive symptoms of Sz. There two types:

1. Typical antipsychotics (first generation):
   Chlorpromazine
   Haloperidol
2. Atypical antipsychotics (newer drugs):
   Clozapine
   Olanzapine
   Aripiprazole

Question 2

Typical antipsychotics

Answer 2

The first generation of antipsychotic drugs.
Chlorpromazine
Haloperidol

Strengths:
Effective in reducing positive symptoms by blocking the D2 receptors in the synapses of the brain that absorb dopamine and hence reducing the action of dopamine.

Limitations:
They block all types dopamine actions in other parts of the brain which often come with severe side effects which can decrease drug adherence. Especially if the patient has delusions of persecutions and believe the drugs are to harm them.

Question 3

Chlorpromazine

Answer 3

First antipsychotic drug and was developed in the 1950s.
It had a calming effects on participants.

Strengths:
Reduces effects of dopamine by physically blocking dopamine receptors, which helps reduce positive symptoms.

Limitation:
Blocks all type of dopamine action across the brain, which leads to sever side effects.
Low potency- patient has to take a high dose for it to be effective. Which is bad due to its side effects

Side effects:
Chlorpromazine works on a number of other systems. It blocks serotonin receptors and while this reduces anxiety it also increases risks of depression.

Also blocks noradrenaline receptors which lead to dry mouth and lowered blood pressure.

Causes problems with motor movements. Some patients report dystonia, which can be long-term.

Question 4

Haloperidol

Answer 4

Originally developed for surgery use but found to have calming effects which work to reduce positive symptoms of Sz.

It rebalances dopamine to improve thinking, mood and behavior.

Strength:
Around 50 times more potent than chlorpromazine.
Effective in combating hallucinations and delusions. Also found to help with disordered thinking and lack of motivation.
Cheap to produce

Limitation:
Severe side effects, common, very common and rare
Severity of side effects lead to patients not taking their medication which could cause a relapse

Side effects:
Very common side effects- severe motor conditions
Some have opposite effects- some participants report having difficulties sleeping while others report sleepiness

Question 5

Atypical antipsychotics

Answer 5

Second generation antipsychotics.
Clozapine
Olanzapine
Aripiprazole

These attempt to target D2 dopamine activity in the limbic system but not D3 receptors in other parts of the brain. This is as an attempt to reduce side effects.

They first came to use in the 1970s.

They bind to dopamine, serotonin and glutamate receptors.
They work on negative symptoms and improve mood, cognitive functions and reduce depression and anxiety.

Strength:
Less side effects that typical drugs, no motor side effects
Often used for first episode Sz, which is good due to less side effects. This is because first episode patients might be reluctant to take drugs out of fear that they are given with the intention of harm (delusion if persecution).
More affective in treating megative symptoms

Question 6

Clozapine

Answer 6

Strengths:
Useful in reducing positive symptoms in most patients.

Limitation:
Some patients are resistant to the treatment with this drug.
No motor side effects but one severe side effects that makes psychiatrists reluctant to prescribe it.

Side effect:
Agranulocytosis - causes a decrease in white blood cells. This can at times be large enough to cause death.
Therefore patients prescribed with this are asked to take regular blood tests to detect any decrease in white blood cells before it gets dangerous.

Question 7

Olanzapine

Answer 7

Only prescribed early in patient’s experience of Sz.

Strength:
Extremely effective on both positive and negative symptoms but never for long period of time.

McGlashan et al. showed that prodromal schizophrenic individuals who were given olanzapine were less likely to develop Sz than those were not given it.

Side effects:
Causes obesity and/or diabetes in many patients if used for extended periods of time.

Question 8

Aripiprazole

Answer 8

Instead of blocking dopamine receptors it sits at receptor sites and promotes a partial response weaker than the effect of real dopamine.

Strengths:
Helps with both overproduction and underproduction of dopamine across various areas of the brain.

Side effects:
Nausea and insomnia
Unlike more antipsychotic drugs it is rarely associated with diabetes or obesity.