The Medical Model Flashcards
Biochemical explanation of depression
Depression is related to low levels of the neurotransmitter serotonin in the nervous system so it can’t diffuse across the synaptic cleft to bind the the post synaptic neurone (absorbed back into pre-synaptic). The messages of ‘happiness’ therefore aren’t transmitted and the body doesn’t respond in the appropriate way.
Treat depression by blocking reuptake of serotonin into presynaptic neurone.
Biochemical explanation of schizophrenia
Excess neurotransmitter dopamine in the nervous system.
Cured by blocking receptor in post synaptic neurone to prevent overload of dopamine reaching post synaptic neurone.
Genetic explanation of mental illness
Disorders can be passed from parents to children through genetic transmission.
Research by Gottesman et al shows increased risk if children have two parents with bipolar disorder or schizophrenia compared to those with one. However children don’t always have the same disorder their parents have so there may be environmental or individual differences that make some people more prone to diagnoses of mental illness.
Study by Gottesman and Shields they found if one twin had schizophrenia there was 58% chance their identical twin had it. If the twins weren’t identical there was only a 12% chance. The study suggests a strong genetic component to schizophrenia but that its occurrence can’t be explained by genetics alone.
Evolutionary theory:
It is suggested that we have inherited traits that have a beneficial effect on our chances of survival. This could be an explanation for phobias because people with a fear of e..g spiders and snakes stayed away from them so could survive and reproduce while people without the fear died (e.g. due to snake bite) and didn’t reproduce.
Ohman (1975) gave participants electric shocks at the same time as they saw a picture of a house, a snake or a human face. It was easier to condition a fear response for snakes suggesting an inherited biological predisposition to fear snakes more.
Brain abnormalities explanation of schizophrenia
Brown et al- in post mortem studies found the brains of schizophrenics were 6% lighter than those with an affective disorder and had enlarged lateral ventricles (hollow areas in brain), thinner para-hippocampal cortices (episodic memory, visuospatial processing).
Weinberger- by doing MRI scans with identical twins (one with schizophrenia and one without) found that there were differences between the two groups in the prefrontal cortex and the hippocampus volume.
Brain abnormalities explanations of depression
Research shows people with depression have a smaller hippocampus volume than people without depression. This may be because depressed people experience stress which leads to the release of cortisol (which destroys hippocampus cells). Hippocampus cells then can’t respond to serotonin normally.
Sheline et al- in a study of elderly of elderly women who’s depression was ‘in remission’ it was found these women’s hippocampi was was smaller than other women their age.
Treatment e.g. drug therapy, surgery (if brain tumours producing symptoms of disorder).
Key research- Gottesman.
Aim: to investigate a large sample the probability of a child being diagnosed with a mental disorder if either or both of their parents had this disorder.
Sample: anyone in Denmark aged 10-52 in Jan 2007 with a clear link to their biological parents. Sample of 2.7 million people and their parents.
Procedure: data from psychiatric central register, he identified 4 groups of people:
- Both parents admitted to psychiatric hospital with schizophrenia, bipolar disorder or depression.
- One parent admitted for schizophrenia, bipolar disorder or depression.
- Neither parent admitted with diagnosis of disorder.
- The general public (no data available on whether they had parents admitted or not).
Findings:
Both parents: schiz- 27.3% bip- 24.9%
One parent: 7% and 4.4%
Neither: 0.86% and 0.48%
General population: 1.12% and 0.63%
-Seemed to be genetic overlap between schizophrenia and bipolar (if both parents had schiz, 10.8% of offspring admitted with bipolar).
-If both parents admitted, 67.5% of offspring were admitted for any disorder. If both had bipolar, 44.2% admitted. If neither admitted, 11.9%. General population, 14.1% offspring admitted.
-At age 52, very few people receiving fresh diagnosis of schizophrenia but at the same age fresh bipolar diagnoses still being made.
Conclusions and comments:
- Where both parents are admitted with bipolar or schizophrenia, their offspring is at super high risk of being admitted with a disorder.
- Uses of this study: personal decision making e.g. marriage, child bearing, adoption.
- Must not be ignorant of the ‘Nazis’ barbaric use during the Third Reich of genetic information to justify their eugenics policies of sterilisation and murder.
- ‘ by joining advances in molecular genetics that are adapted for use in epidemiological screening, our kinds of data with the risk groups described might lead to a large and rapid step forward in the understanding of the etiologies of major mental disorders’.
Evaluation of Gottesman key research
Nature/ nurture- nature. The findings support the view that genetics plays a major role in your likelihood to develop a mental disorder (depression, bipolar and schizophrenia).
However it doesn’t take into account that living with a parent with a mental disorder could cause you to learn certain behaviours.
Sampling bias- those aged 10 may develop a mental disorder later in life. However very large ( representative) sample and large age range 10-52. People with bipolar and depression are more likely to be treated as outpatients rather than being admitted to hospital so this may skew data.
Ethnocentrism- Denmark may not be representative of the likelihood of being diagnosed with a mental disorder as it’s not as ethically diverse as other countries.
Used the ICD to diagnose mental disorder not the DSM.
Healthcare in provided free in Denmark which could result in differences in the rate of diagnosis or how often they’re admitted to a mental hospital compared to other countries.
Freewill/ determinism- determinism as study suggests that if your parents have a mental disorder you are much more likely to have one later in life as well. Don’t take into account lifestyle choices.
Drug therapy- biological treatment of disorder (SSRI’s)
Aim to restore normal levels of neurotransmitter action by selective serotonin reuptake inhibitors (SSRIs). By blocking the uptake of the neurotransmitter into the pre-synaptic neurone, there’s more in the synaptic cleft so more can bind to the receptors on the post-synaptic neurone, triggering an electrical impulse to continue down the neuronal pathway.
SSRI’s used to treat depression (and anxiety).
Brain stimulation
Electro-convulsive therapy (ECT) where a patient has electrodes placed on their temples. An electric shock is passed into their brain in an attempt to trigger an epileptic seizure to ‘jump start’ the brain to relieve symptoms of a mental disorder. It is administered under anaesthetic.
Evaluation of applications
SSRI’s are safe for medically ill or frail patients and safe in overdose. No withdrawal effects when stopped abruptly and no dependant develops. Can be expensive and cause sexual problems.
ECT has risks such as physical trauma and heart problems, short term confusion and longer term memory loss.
