Biological explanations and treatments Flashcards

Question

A03) Evaluation

Answer 1

Challenges A01: P) Challenge - The idea that brain tissue differences are an effect of having the disorder rather than being due to genetic factors. E) Boos et al (2012) - performed MRI scans on 155 schizophrenics and 186 of their non schizophrenic siblings. Findings: Schizophrenics had REDUCED GREY MATTER DENSITY AND CORTICAL THINNING. Therefore, there are a number of neural correlates of sz symptoms (positive + negative). C) However, does the unusual activity in a brain region cause the symptom? There could be other explanations for this correlation. For example, the correlation between levels of activity in the ventral striatum and avolition. It is possible that something is wrong in the striatum, causing the negative symptoms. On the other hand, it could be that the NEGATIVE SYMPTOMS THEMSELVES means that LESS INFORMATION passed through the striatum, resulting in REDUCED ACTIVITY. C) Links back to what comes first?

Answer 2

Challenges A01: P) The existence of NC in sz tells us little in itself. E) Sz can take place in the ABSENCE of a family history of the disorder. One explanation for this - a mutation in parental DNA eg. sperm cells. Can be caused by radiation, poison or a viral infection. C) Evidence for this comes from a study by Brown et al (2002) which showed a POSITIVE CORRELATION between PATERNAL AGE and RISK OF SCHIZOPHRENIA. Increasing from 0.7% with Fathers UNDER 25, to over 2% in Father OVER 50. C) Therefore, there alternative explanations which are backed up by studies.

Answer 3

Antipsychotics - Drugs used to treat schizophrenia. Typical antipsychotics - Traditional, old drugs, first line developed to treat schizophrenia. Atypical antipsychotics - Newer drugs Antagonist - Blocks dopamine, lowers the level. Agonist - Increases transmission, heightens the level. D2 receptors - Receptors for dopamine on the post synaptic neuron. Agranulocytosis - A side effect of the drugs, reduces the white blood cells. White blood cells are responsible for fighting infections. Tardive dyskinesia - A side effect of the drugs, causes tremors and pacing. Globally, around $14.5 BILLION is estimated to be spent on antipsychotics each year.

Answer 4

Used PRIMARILY to COMBAT the POSITIVE SYMPTOMS, such as hallucinations and thought disturbances, which are products of an overactive dopamine system. Developed in the 1950's, known as "conventional" antipsychotics. The basic mechanism is to REDUCE THE LEVEL OF DOPAMINE AND SO REDUCE THE SYMPTOMS. Dopamine ANTAGONISTS - They bind to but do not stimulate dopamine receptors (particularly in the mesolimbic dopamine pathway), thus BLOCKING THEIR ACTION. By reducing stimulation of the dopamine system in the mesolimbic pathway, antipsychotics ELIMINATE the hallucinations and delusions. Hallucinations and delusions --> Usually diminish within a FEW DAYS of beginning medication. However, other symptoms may take SEVERAL WEEKS before a significant improvement is seen. The effectiveness of the dopamine antagonists in reducing these symptoms, led to DH development. Kapur et al (2000) estimate --> between 60% and 75% of D2 receptors must be BLOCKED for these drugs to be effective. However, to do this, a similar number of D2 receptors in OTHER AREAS of the brain need to be BLOCKED, leading to undesirable side effects. To address this problem, atypical antipsychotic drugs have been developed. Criticism: Don't help negative symptoms and are expensive.

Answer 5

"Second generation" antipsychotics Three main differences to the first gen: - Lower risk of extrapyramidal side effects eg. inability to sit still, tremors, stiff muscles, involuntary facial movements. - Have a beneficial effect on negative symptoms and cognitive impairment. - Suitable for treatment - resistant patients. Like with typical drugs, these also block D2 receptors. However, they only TEMPORARILY occupy the D2 receptors and then RAPIDLY DISASSOCIATE to allow NORMAL DOPAMINE TRANSMISSION. This rapid dissociation of atypical antipsychotics is thought to be RESPONSIBLE for the less side effects found within these drugs compared to conventional ones. They have very little effect on the dopamine systems that control movement, so tend NOT to cause MOVEMENT PROBLEMS (found with typical). However, atypical antipsychotics have a STRONGER AFFINITY for SEROTONIN receptors and a LOWER AFFINITY for D2 receptors. This explains the different effects of atypical compared to typical.

Answer 6

Weakness of RM: P) Weakness - Likelihood of side effects, ranging from mild - serious - fatal. E) Typical --> associated with dizziness, agitation, sleepiness, stiff jaw, weight gain and itchy skin. Long term use --> Tardive dyskinesia Most serious side effect of typical --> neuroleptic malignant syndrome --> leads to high temp, delirium, coma ---> can be fatal. C) Contrast --> Atypical ones have fewer side effects, because of their mechanism of action --> but do still have side effects eg. agranulocytosis. C) Suggests that AP's may not be appropriate for all patients and should be PRESCRIBED WITH CAUTION. Side effects can be so distressing for patients that they STOP taking the medication entirely --> impacts the effectiveness of the drugs.

Answer 7

Supports A01: P) Strength of chlorpromazine - supporting studies for its effectiveness. E) Thornley et al (2003) - Reviewed studies comparing the effects of chlorpromazine and a placebo. Data from 13 trials of 1121 pp's found that CP was associated with better overall functioning and reduced symptom severity. E) Furthermore, Leucht et al (2012) - Meta analysis of 65 studies involving nearly 6000 participants. All had been given antipsychotics. Some were taken off theirs and given a placebo instead. Findings: Within 12 months, 64% of those on the placebo had relapsed. 27% relapsed on the AP drugs. E) Meltzer et al (2012) --> concluded that clozapine is more effective than typical AP's and other atypical AP's and that it is effective in 30-50% of treatment - resistant cases, where typical AP's have failed. L) This provides strong evidence for the effectiveness of antipsychotics, especially chlorpromazine and clozapine.

Answer 8

Weakness of RM: P) Ethical issues with anti-psychotics E) Laing - Anti Psychiatry movement - Says they restrict the mind and are "chemical straitjackets". He also states that if psychedelics eg. magic mushroom can be banned, why can't anti-psychotics, especially because the side effects are much worse. C) Contrast point - Protects themselves and others from harm. Could be supporting ethics (protection from harm). C) However, they do go against free will, as patients are sectioned and drugs are given on time relapse, which could be a major ethical issue.

Answer 9

Weakness of RM: P) Weakness - Side effects, death and psycho-social consequences. If these were taken into account, a cost-benefit analysis of its advantages would probably be negative. E) USA - Large out of court settlement --> awarded to a tardive dyskinesia sufferer on the basis of the Human Rights Act --> no one should be subjected to inhuman or degrading treatment/punishment. C) Additionally, it is widely believed that AP's have been used in hospital to make patients calmer and easier to deal with, rather than for the patients benefit. Additionally --> Ethical - patient w/ severe symptoms --> may not be able to give fully informed consent. C) Highly unethical - breaks human rights, mostly negative.

Answer 10

Challenges A01: P) Challenge --> Their effectiveness may be highly exaggerated. E) Healy (2012) - Argued that some successful trials of their effectiveness have had their data published MULTIPLE times. Exaggerates the evidence for + effects. C) Furthermore --> As AP's have calming effects --> easy to demonstrate that they have some positive effects on patients. NOT THE SAME as saying they REALLY REDUCE the SEVERITY of symptoms. C) Not really a wide range of data to support their effectiveness. Highly exaggerated.

Answer 11

Chlorpromazine - Blocks dopamine receptor sites. Thus decreases dopamine activity. Side effects: muscle tightening in neck and jaw, tardive dyskinesia, depression, NMS - epilepsy. Barlow + Durand (1995) - Effective in reducing schizophrenic symptoms in about 60% of cases. Most impact on +, still suffer from severe - symptoms. Haloperidol - Blocks dopamine receptor sites. Thus decreases dopamine activity. 55% relapse rate - Schooler et al (2005) Side effects: muscle tightening in neck and jaw, tardive dyskinesia, decrease in emotional spontaneity and motivation, weight gain, NMS. Schooler et al (2005) - Randomly allocated 555 patients in first episode of sz. Either treated w/ haloperidol or risperidone. 75% in both groups showed a reduction in symptoms. However, 75% drop out.

Answer 12

Clozapine - Blocks both dopamine and serotonin receptor sites. Side effects: Similar to typical AP's, but tardive dyskinesia is much reduced. Fewer side effects than typical or first gen anti-psychotics. Rare side effect: agranulocytosis - dangerously low level of white blood cells can be FATAL. Pickar et al (1992) - Compared it with other neuroleptics and a placebo --> found clozapine to be the most effective in reducing symptoms, even in patients who had previously been treatment resistant. 72% compliance rate. Risperidone - Blocks both dopamine and serotonin receptor sites. 45% relapse rate compared to 55% with haloperidol (Schooler et al-2005) Side effects: Fewer than haloperidol; weight gain, severe anxiety, sedation, sexual dysfunction, low blood pressure, stuffy nose. Emsley (2008) - Found that patients who were injected with it early in the course of the disorder had LOW relapse rates and HIGH remission rates. 84% of patients showed at least a 50% reduction in both + and - symptoms. 64% went into remission.