Biological treatments for schizophrenia Flashcards
What is the purpose of AP medication?
To reduce, modulate or stabilise the balance of dopamine in 4 key dopamine pathways, and alleviate some of the symptoms of SZ. It must be taken on a regular basis and takes 7 days to show an effect. Positive symptoms are dramatically reduced and slowly some negative symptoms subside.
What are typical AP drugs?
Typical antipsychotics e.g. Chlorpromazine and haloperidolANTAGONISTS (reduce D2) e.g reduce hallucinations and thought disturbance- products of an overactive Dopamine system as they bind to dopamine receptor (D2) and block their action in the mesolimbic pathway.
What is the action of typical AP drugs?
By binding to D2 receptors sites, this lowers dopamine transmission and reduces some positive symptoms. Kapur found that approximately 60 - 75% of D2 receptors were blocked in the mesolimbic pathway.
What are the side effects of typical AP drugs?
Typical antipsychotics are more likely to cause extrapyramidal side effects in which motor control is sometimes severely impaired, causing tremors, spasms, muscle rigidity, and the loss of control and coordination of muscle movement. In some cases, the symptoms may become permanent even after the treatment is stopped.
What are the motor symptoms of typical AP drugs?
Dystonia Painful and lasting muscle spasms predominantly affecting the head, neck, and tongue Facial grimacing.
Tardive dyskinesia: Involuntary movements of the mouth and tongue; limbs, face, and respiratory muscles caused by chronic use of antipsychotic drugs. Repetitive chewing and lip smacking
Akathisia:Restlessness/compelling urge to move & Inability to sit or stand still
Agranulocytosis: a rare, drug-induced blood disorder that is characterised by a severe reduction in the number of white blood cells (granulocytes) in the circulating blood
What are types of atypical AP drugs?
Clozapine, olanzapine and Seroquel
What are atypical AP drugs?
Are used to combat the positive symptoms but in ADDITION, claim beneficial effects on relieving negative symptoms and cognitive impairment. So are DOPAMINE MODULATORS
These act on the D2 receptors to block their action but also act on serotonin receptors (5-HT2 receptors) as SCH patients may also have increased levels of serotonin , hence can help with symptoms other than just positive symptoms.
This sensory pathway is involved with emotions and sensations of pleasure. Reducing the hyperactivity of dopamine here should reduce positive symptoms like delusions
By using a hit and run action (rapid dissociation) AP have their effect on dopamine receptors and then quickly leave the receptor site.
This type of action allows AP to have an effect, but then receptors quickly become available for naturally occurring dopamine before the next dose. This action helps avoid some motor side effects
What are the symptoms of atypical AP drugs?
Atypical antipsychotics are far less likely to cause extrapyramidal side effects. With that being said, they are known to cause weight gain, metabolic problems, and sexual side effects, hypertension etc
What is the action in the mesolimbic dopamine pathway?
The sensory pathway is involved with emotions and sensations of pleasure. Reducing the hyperactivity of dopamine here should reduce the positive symptoms like delusions. By using a hit and run action (rapid dissociation), APs have their effect on dopamine receptors and then quickly leave the receptor site. This type of action allows APs to have an effect, but then receptors quickly become available for naturally occurring dopamine before the next dose. This action helps avoid some motor side effects.
What is the action in the nigrostriatal pathway?
This sensory pathway has a role in controlling movement, and as such involves dopamine and serotonin (the blocking / reducing of dopamine receptor sites here can lead to motor side effects). However, presence of serotonin in the pathway antagonises dopamine release, so the AP action is to antagonise serotonin receptors but also stimulates an increase in levels of natural dopamine in dopamine receptors in this pathway and in the prefrontal cortex. Hence, natural dopamine fills receptor sites in other pathways and prevents blockade from APs in this area. This helps tackle negative symptoms and reduces motor side effects.
BIOLOGICAL TREATMENT - Supporting research?
Davis analysed results of 29 studies of 3519 patients to find out about the effectiveness of antipsychotic drugs. They found a relapse in 55% where a placebo was swapped in compared to 19% for those still taking APs. It is therefore effective.
BIOLOGICAL TREATMENT - Alternative treatments?
CBT can help patients when they are used alongside APs, as when they are combined, the medication would suspend delusionary thoughts, allowing patients to address the more cognitive issues.. It is therefore useful to consider alternative treatments alongside APs.
BIOLOGICAL TREATMENT - Reductionist?
Basis of treatment is biological, at the neurochemical level, which ignores psychological factors. For example, CBT or token economy should be considered alongside to treat complex disorders as the biological focus may be too simplistic
BIOLOGICAL TREATMENT - Effective?
Elesser carried out a longitudinal study and found that AP medication did not help everyone and rarely removed all symptoms. Typical AP medication helped 65% of patients and atypical medication helped 85% of patients. We therefore have to consider different treatments.
BIOLOGICAL TREATMENT - Methodological issues?
Ross and Read re-analysed the data presented by Davis and suggested that 45% of those using the placebo did therefore benefit. Also 81% of the AP group benefited just as the 45% did. Methodological issues with the way that data is interpreted to support a hypothesis.
