Biological therapies

Antipsychotic drugs are the most common treatment for schizophrenia. They can be taken as tablets or in the form of syrup, and even as an injection. They can be divided into two types; what are they?

• Typical antipsychotics (traditional)

• Newer atypical antipsychotics

Describe typical antipsychotics

• Typical antipsychotics have an association with the dopamine hypothesis.

• They work by acting as a dopamine antagonist. Antagonists are chemicals that reduce the action of a neurotransmitter. They block dopamine receptors in the synapses of the brain, which reduces the action of dopamine.

• This will normalise the neurotransmission in key areas of the brain, reducing symptoms like hallucinations.

• They also have a sedative effect. Chlorpromazine is often used to calm patients not only with schizophrenia but with other conditions.

• This is often done when they are first administered to hospital and are very anxious.

Describe atypical antipsychotics

• These have been used since the 1970’s. Their aim was to maintain and improve upon the effectiveness of previous drugs for psychosis, whilst also minimising the side effects.

• It binds to receptors in the same way as Chlorpromazine, but it also acts on serotonin and glutamate receptors. It is believed that this helps improve mood and reduce depression and anxiety in patients, and that it may improve cognitive functioning.

• The mood enhancing effects mean it may be prescribed if the patent is at high risk of suicide.

• There is some evidence that is may lead to fewer side effects than other antipsychotics.

Describe one typical antipsychotic

Chlorpromazine was created in the 1950s and can be taken as a tablet, syrup or injection. If taken as a tablet it must be administered daily up to a maximum of 1000mg. Has a sedative effect. Chlorpromazine is often used to calm patients not only with schizophrenia but with other conditions. This is often done when they are first administered to hospital and are very anxious.

Describe two atypical antipsychotics

Two examples of atypical antipsychotics are Clozapine and Risperidone.

• Clozapine was developed in 1960’s but was withdrawn in 1970’s following the death of some patients due to a blood condition called agranulocytosis. It was then only used when previous treatments had failed. It is still used today, and people taking it will have regular blood tests to ensure they are not developing agranulocytosis. It binds to receptors in the same way as Chlorpromazine, but it also acts on serotonin and glutamate receptors. It is believed that this helps improve mood and reduce depression and anxiety in patients, and that it may improve cognitive functioning. The mood enhancing effects mean it may be prescribed if the patent is at high risk of suicide.

• Risperidone is a more recent atypical antipsychotic, created in the 1990s. It was designed to be as effective as Clozapine but without the serious side effects. Like Clozapine, Risperidone binds to dopamine and serotonin receptors. It binds more strongly to dopamine receptors than Clozapine and therefore is effective in much smaller doses. There is some evidence that is may lead to fewer side effects than other antipsychotics.

Give a strength of drug therapy (Chloropromazine)

• There is supporting evidence for the effectiveness of both typical and atypical antipsychotics.

• Thornley reviewed studies comparing the effects of take Chlorpromazine to controls taking a placebo. Data from 1121 participants showed that Chlorpromazine was associated with better overall functioning and reduced symptom severity compared to a placebo. For some, they also found that relapse rates were lower when Chlorpromazine was taken.

Give a strength of drug therapy (Clozapine)

• There is supporting evidence for the effectiveness of both typical and atypical antipsychotics.

• Meltzer concluded that Clozapine was more effective than typical and other atypical antipsychotics. It was also effective in 30-50% of treatment resistant cases where typical antipsychotics had failed. Both studies strengthen the use of biological therapies as they are evidence that antipsychotics are in general reasonably effective as a treatment for schizophrenia.

Give 1 limitation of drug therapy (Healy)

• Although there is a mass of evidence for the effectiveness of antipsychotics, there has been some serious challenges to their usefulness.

• Healy suggested that some successful trials have had their data published multiple times, exaggerating the evidence for positive effects.

• Also, as they have a calming effect on the patients, it is easy to demonstrate that they have a positive effect on the patient. However, this is not the same as saying that they treat psychosis. Finally, most studies only assess short-term benefits as opposed to the long-term benefits.

• Overall, therefore it is difficult to conclude that antipsychotics drugs are effective as there are many issues with the supporting studies.

Give 1 limitation of drug therapy

• A problem with antipsychotics is the side effects they can cause, ranging from mild to the serious and even fatal. Typical antipsychotics can cause side effects such as dizziness, agitation, sleepiness, and weight gain.

• Long term use can result in tardive dyskinesia, which manifests as involuntary facial movements such as blinking and lip smacking. The most serious side effect is neuroleptic malignant syndrome (NMS). This is due to the drug blocking dopamine in the hypothalamus which helps to regulate several body systems.

• This results in high temperature, and comas, and it can even be fatal. Atypical antipsychotics were developed to reduce the frequency of side effects and have generally succeeded in doing this.

• However, some still exist and those taking Clozapine need regular blood tests to alert doctors to early signs of agranulocytosis.

• Therefore, side effects are still a significant weakness of antipsychotic drugs.

Give 1 limitation of drug therapies being based on the original dopamine hypothesis

• The use of antipsychotics is based on the original dopamine hypothesis, the idea that higher than normal levels of dopamine in the subcortex are the cause.

• However, there is evidence that this is not a complete explanation for schizophrenia, and that for some there may be too little dopamine in other parts of the brain. If this is true it is not clear how antipsychotics can help with schizophrenia when they reduce dopamine activity.

• The modern understanding suggests that antipsychotics should not work.

• This is a weakness for the use of antipsychotics and has undermined the faith that some people have that antipsychotics do work.