Paper 3 - Mental Health 2 - The Medical Model Flashcards
(34 cards)
what is biochemical principles
- focuses on abnormal levels of neurotransmitters - too much or too little
- neurones and synapses - messages are transmitted electrically around the brain and body via neurones. there are around 100bilion neurones in the brain. they link at synapses
- neurotransmitters - information is transmitted chemically at the synapse, the electrical charge in the presynaptic nurone causes neurotransmitters to be released which activates receptors in the postsynaptic neurone. Some neurotransmitters are excitatory and some are inhibitory
- the activation of the subsequent neurones depends on the quantity of the neurontransmitters at the synapse too few and the threshold level is not reached.
what is the original dopamine hypothesis for schizophrenia
- the original hypothesis suggested that people with schizophrenia produce an eccessive amount of dopamine in the brain, particularly in the limbic system
what is the revised dopamine hypothesis for schizophrenia
- schizophrenia is not due to the excess production of dopamine, but there is an excessive amount of dopamine receptors at the post synaptic neurone and the receptors are more sensitive than normal
- this means more dopamine is absorbed into the next neurone which leads to an excess of dopamine in various pathways in the brain
- this is particularly the case for the D2 subtype of of dopamine receptors.
- this can occur due to a genetic dysfunction or some form of damage to the brain during development like disease, infection or injury.
what is the cause for the positive symptoms of schizophrenia
- hypofunction - too much dopamine activity - in the mesolimbic pathway.
- This is responsible for motivation, emotion and reward.
- This can explain unusual behaviour and perceptions
what is the cause of the negative symptoms of scizophrenia
- linked to erratic dopamine function in the mesocortical pathway
- this is responsible for executive function (mental health and self regulation)
- this can explain the cognitive deficits and problems with affect experienced during an episode
what is the research evidence of the dopamine hypothesis by Seeman
- Philip seeman reported several strands of evidence that provide support for the dopamine hypothesis…
- drugs that increase levels of dopamine increase some positive symptoms like hallucinations
- antipsychotic drigs block dopamine receptors and reduce symptoms
- post-mortems of schizophrenic brains show higher density of D2 receptors than normal brains
explain twin studies for genetic explanations by Glatt and Genains
- according to Stephen Glatt a range of twin studies show that the concordance rate for schizophrenia is MZ (identical) twins is about 46% to 53%
- in DZ twins it is about 15%
- However this is a meta analysis
- The Genains were identical female quadruplets had identical genes and they developed the disorder before 24 years.
- But there is also evidence of environmental influences, the father physically abused the girls.
- this shows a interactionist approach
- nature - genes - interacts with nurture - treatment by parents .
- they have a genetic predisposition to the disorder but it is triggered or enforced by the environment
explain genome association studies for genetic explanations by Ripke
- Ripke conducted a Genome study
- comparing genotypes of 36,989 people with the disorder
- and 113,075 non affected control pps.
- they found that 108 separate genetic variations were associated with schizophrenia
explain enlarged ventricles theory for brain abnormality explanations
- people with schizophrenia have enlarged ventricles in their brain.
- enlarged ventricles lead to a reduction in the total amount of grey matter (functional neurones) and brain size, particularly in these areas…
- temporal lobes - loss of grey matter causes auditory hallucinations
- frontal lobes - loss may explain incoherent speech and perceptual disturbance like delusions
- thalamus - loss may lead to auditory and verbal hallucinations
- the longer the person has schizophrenia the less grey matter in their brain
- this stops when the patient takes antipsychotic medications, suggesting that grey matter is associated with the disorder
explain the research evidence for ventricle and brain size by Hulshoff Pol
- Hilleke Hulshoff Pol compared 159 people with schizophrenia with 158 healthy individuals
- there can be up to a 30% increase in the size of the ventricles of patients with schziophrenia.
- larger ventricles means less grey matter in the brain - less functionality in the brain
what is the method of Gottesman’s study on genetic explanations
- secondary data from a database of hospital records
what is the aim of gotessman’s study
- to use a larger sample than previous research to investigate the likely hood of offspring being diagnosed with schizophrenia, bipolar disorder or another disorder if their parents had been diagnoed
what is the sample of gottesman’s study
- danish civil registration system
- The Danish psychiatric Register contains info about patients admitted based on ICD-8 or ICD-10
- ages 10 or over
- over 3 million people
- group 1 - couples who has both been admitted
- group 2 - couples where 1 partner was admitted
- group 3 - no parents had any mental illness
- group 4 - no data on diagnosis
what is the procedure of Gottesman’s study
- data on each offspring was linked with parents psychiatric history
- using the Civil registration the researchers established who their parents were and if they were on the psychiatric register and idenitified their mental disorder
what were the results for Gottesman’s study
- if both parents had schizophrenia there is a 27.3% chance of the children having it
- if one parents had it there is a 7% change
- if neither parents had it there is a 0.86%
what are the conclusions of Gottesman’s study
- if both parents have a serious psychological disorder this significtantly increasses the risk of the child developing this disorder
- one parent increases the risk but more increased with 2 parents
- the genetic explanation is supported as the research shows an increase chance of developing a disoder if direct relatives have it
what is the diathesis stress model
- suggests that people may be predisoppsd to a menrtal health condition and hen a triffer causses the condition to show symptoms
- diathesis - genetic, biological or early childhood experience
- stress - new experience or environmental trigger
- holistic, interactionist approach
how does Gotessman’s research explain the medical model
- because it is a biological explanation of psychological disorders - genetics
- children had an increased risk of being diagnosed with schizophrenia if their parents had been diagnpsed
- research also demonstrates an increased risk of developing a disorder if parents have any psychological disorder, suggesting that the same genes may underlie a number of disorders
- the relationship is not 100%, suggesting other factors as the cause
- the results are useful for genetic counceling helping people decide on having children
- Gotessman warns against misuse of this data as evidence for eugenics
evaluate validity in this topic
- large sample in Gottessmans research means it can be generalised
- Gotessman used ICD which is believed to be valid
- however the validity of individual diagnosis depends on many factors, some symptoms may overlap so diagnosis being incorrect
- Seeman pointed out various methods wich proved the dopamine hypothesis
- does schizophrenia cause brain abnormality or does brain abnorality cause schizophrenia. however Karlsgot found the differences of a schizophrenic brain of people at risk in very early stages which suggests the brain abnormalities come first
evaluate reliability in this topic
- MRI scan reliability is poor (Haijmas study)
- reliability of diagnosis for depression is good using DSMV - Brown found a correlation of 0.67 for different clinicians diagnosing the same person
- Leucht - in a review of 6493 pps using antipsychotics for scizophrenia the relapse rate was 27% throughout the 116 studies showing replication the results = external reliability
evaluate socially sensitive research in this topic
- interesting behaviour - 1% of the population develop schizophrenia. However risk increases depending on genetics - Gottesman. this allows development of treatments
- distress - Gottesman’s study parental guilt
- policies - eugenics policies - people with disorders are prevented from having children or killed
evaluate ethics in this topic
- informed consent - no pps in Gotessmans study knew their data was used but data was anonymous
- no direct harm - no pps manipulated but knowledge of increased ridk may be upsetting outside the study
- deception - not telling pps aim Leucht reviewed 116 studies of 6493 pps with schizophrenia, 27% on antipsychotics relapsed vs 64% on placebo - they did not know it was a placebo
- cost benefit analysis -ethical rules broken for a few people vs the benefit on developing and testing new medications and genetic councelling to help large numbers of people make informed decisions and get well
evaluate nature/nurture in this topic
- nature - schizophrenia caused by genetics gotessman
- nurture - brain abnormalities possibly could be caused by brain damage from accidentsm even cannabis use which could cause enlarged ventricles - Hulshoff
- interactionist - The diathesis stress model proposes a genetic predisposition triggered by a life experience
evaluate determinism/ freewill in this topic
- biological determinism - Hulshoff study
- Environmental determinism - brain abnormalities can be caused by accidents - Seeman
- freewill - some people teach themselves how to control hallucinations by humming or listening to loud music.