Schizophrenia: Drug therapy Flashcards
What is drug therapy?
Involves the treatment of mental disorders such as schizophrenia through the use of antipsychotics to reduce symptoms of the disorder.
What are two types of biological treatments to schizophrenia?
- Typical (conventional antipsychotics)
- Atypical antipsychotics
What are antipsychotics and how do they help a person with schizophrenia?
Antipsychotic medication helps the person with the disorder function as well as possible in their life, whilst at the same time increasing their feelings of subjective well-being. Antipsychotics are usually recommended as the initial treatment for the symptoms of schizophrenia, after which clinicians tend to use a combination of medication and psychological therapy to manage the disorder. All antipsychotics work by reducing dopaminergic transmission i.e reducing the action of the neurotransmitter dopamine in areas of the brain associated with the symptoms of SZ.
What are typical antipsychotics?
Such as Chlorpromazine are used primarily to combat positive symptoms of SZ such as hallucinations and though disturbances- products of an overactive dopamine system.
What are atypical antipsychotics?
Such as clozapine also combat positive symptoms but in addition, there are claims that they have some beneficial effects on negative symptoms as well.
What is the role of atypical antipsychotics in treating schizophrenia?
Atypical antipsychotics (also known as second-generation antipsychotics) were developed in the 1990s and are so-called because of three main differences from the first-generation typical antipsychotics. They carry a little risk of extrapyramidal side effects, have beneficial effects on negative symptoms and cognitive impairment, and are suitable for treatment-resistant patients. These drugs also act on the dopamine system by blocking D2 receptors. However, they only temporarily occupied the D2 receptors and then rapidly dissociate allowing normal dopamine transmission. It is this characteristic of atypical antipsychotics that is thought to be responsible for the lower levels of extrapyramidal side effects found with these drugs compared to conventional antipsychotics. Because atypical antipsychotics such as clozapine have very little effect on the dopamine system that controls movement, they tend not to cause the movement problems found with typical antipsychotics. Rapid dissociation is one feature of atypical antipsychotics that distinguishes them from typical antipsychotics, but there are others. Atypical antipsychotics have a stronger affinity for serotonin and a lower affinity for D2 receptors. It is this characteristic that explains the different effects of atypical compared to typical antipsychotics
What is the role of typical antipsychotics in treating schizophrenia?
Also known as conventional first-generation antipsychotics were developed in the 1950s. The basic mechanism of typical antipsychotic drugs is to reduce the effects of dopamine and so reduce the symptoms of schizophrenia. Typical antipsychotics are dopamine antagonists in that they bind to but do not stimulate dopamine receptors, (particularly the D2 receptors in the mesolimbic dopamine pathway), thus blocking the action. Reducing stimulation of the dopamine system in the mesolimbic pathway, antipsychotic drugs such as chlorpromazine eliminate the hallucinations and delusions experienced by people with schizophrenia. Hallucinations and delusions are usually diminished within a few days of beginning medication, although other symptoms may take several weeks before significant improvement is noted. The effectiveness of the dopamine antagonist in reducing the symptoms led to the development of the dopamine hypothesis of schizophrenia.
What is electroconvulsive therapy as a biological therapy?
The idea came from dementia praecox being rare in epileptics. Idea was to induce seizures in patients. ECT works by using an electrical shock to cause a seizure (a short period of irregular brain activity). This seizure releases a rush of chemical neurotransmitters and temporarily alters function e.g. perception and memory.
Weaknesses:
- Side effects may result from both anaesthesia and the etc. including memory loss, confusion, paranoia, nausea, muscle aches and headaches.
+ Tharyana and Adams - ECT is better than placebo but not as good as drugs.
A03:
+ Advantages of atypical over typical antipsychotics
+ Antipsychotics versus placebo
- Ethical problems with typical antipsychotics
- Extrapyramidal side effects
A03: Advantages of atypical over typical antipsychotics
Atypical antipsychotics claim to have a number of advantages when compared to typical antipsychotics. A key advantage of atypical antipsychotics is that patients experience fewer side effects. Atypical antipsychotics, Particularly the more recent newly developed atypical antipsychotics, such as olanzapine and quetiapine are less likely to produce the extrapyramidal effects typically found the typical antipsychotics – therefore patients are more likely to continue with their medication, which in turn means they are more likely to see the reduction in the symptoms instead of relapsing.
A03: Antipsychotics versus placebo
Support for the effectiveness of antipsychotics comes from studies that have compared relapse rates for antipsychotics and placebos. Leucht (2012) carries out a meta-analysis of 65 studies, published between 1959 and 2011, and involving nearly 6000 patients. All patients had been stabilised on either typical or atypical antipsychotics. Some of these patients were taken off their antipsychotic medication and given a placebo instead. The remaining patients remained on their regular antipsychotics. Within 12 months, 64% of those who had been given the placebo had a relapse, compared to 27% of those who stayed on the antipsychotic drug showing the effectiveness of antipsychotics as a drug treatment.
A03: Ethical problems with typical antipsychotics
The problems associated with the use of antipsychotic medication raise significant ethical issues. Critics argue that if side effects, death and psychosocial consequences were taken into account, a cost-benefit analysis of its advantages would most probably be negative. In the US recently, a large out-of-court settlement was awarded to a tardive dyskinesia sufferer on the basis of article 3 of the human rights act 1988, which states that no one shall be subjected to inhuman or degrading treatment or punishment.
A03: Extrapyramidal side effects
Typical antipsychotic drugs can sometimes produce movement problems for the patient. These are called extrapyramidal effects because antipsychotic drugs appear to impact the extrapyramidal area of the brain, which helps control motor activity. The most common are Parkinsonian and related symptoms, so called because they resemble the features of the neurological disorder Parkinson’s disease. More than half of the patients taking typical antipsychotics experience symptoms. When people take antipsychotic drugs for an extended period, a second type of extrapyramidal effect can occur- tardive dyskinesia i.e involuntary movement of the tongue, the face and the jaw. The side effects can be so distressing for the patient that other drugs have been given to control them, or the patient may stop taking the antipsychotic medication completely resulting in relapse.
