Medical Model Flashcards
The Biochemical Explanations of mental illnesses?
Biochemical Explanation of Mental Illness:
A group of neurotransmitters called the monoamines appear to be involved in depression. These include; serotonin (mood, stomach functioning and memory), noradrenaline (present in the hypothalamus & hippocampus – largely responsible for heart rate, concentration, alertness and energy) and dopamine (motivation, pleasure and motor function).
Depression disrupts the activity levels of these neurotransmitters, leaving individuals with altered mood. Serotonin is thought to control the activity of dopamine and noradrenaline. If serotonin levels are low this means that the dopamine is not regulated and in turn had a negative effect on mood.
Messages are transmitted electrically around the brain and body via neurons. Information is transmitted chemically at the synapse (the gap between two neurons). The electrical charge in the presynaptic neuron causes neurons to be released and these activate receptors in the postsynaptic neuron. In addition, the activation of the subsequent neurons depends on the quantity of the neurotransmitters at the synapse, too few, and the threshold to affect the next neuron is not reached i.e. the message is disrupted.
Depression can be explained biochemically in terms of a lack of serotonin in neural synapses, which prevents the passing of ‘happy’ messages along the neural pathway. A lack of serotonin is associated with low mood as serotonin (a neurotransmitter) is unable / insufficient to bridge the synapse gap to pass on stimuli through activation. Another theory is that there is a high level of an enzyme that breaks down the monoamines which then disrupts the messages being passed around the brain, thus impacting mood.
Genetic Explanations for mental illness?
Genetic Explanation of Mental Illness:
Because of the nature of genetics i.e. half of the genes come from each parent, it is possible for one child to inherit a mental health issue and another to not. There must be a genetic reason, why some people are more resilient than others. Most research into genetics takes an interactionist perspective. This is the idea that certain genes interact with the environment, which then influences depressive symptoms.
One theory is the serotonin transporter gene, which (quite clearly) is responsible for producing serotonin in the brain. The serotonin gene comes in 3 different strands: long/long, short/short, or long/short.
It is believed that the short/short gene relates to people having less resilience than others and therefore makes them more susceptible to depression. Research by Brunner also found that a mutation on the x chromosome disrupts activity of monoamines, and this effected a group of brothers moods.
Brain Abnormality?
Brain Abnormality as an Explanation of Mental Illness
Some studies have shown that the pre-frontal cortex (the region of the brain responsible for thinking, emotions and decision making) is smaller in depressed patients compared to healthy patients. Research has also shown that the blood flow in the frontal lobe of depressed patients do not draw on blood flow in the brain as they normally should. This means that it impacts on the functioning of the frontal lobe, which could explain why it leads to depression, as the frontal lobe is responsible for emotion, and could therefore effect emotion and mood.
The amygdala is responsible for processing emotional memories, and feelings of fear. Research has found that activity in the amygdala increases when depressed patients are shown negative stimuli such as a sad video or photo, and when shown positive stimuli, activity of the amygdala decreases! It’s almost like your brain has been wired the wrong way around!
The hippocampus is responsible for processing memories. The hippocampus is significantly smaller in patients with depression – 20% smaller!!! This may be why people with depression process emotional memories in dysfunctional ways. For example, they remember a significant event as being quite negative e.g. during an exam, a student looked over at them and smiled, and this was interpreted as the student laughing at them because they are going to fail! However, it was more likely a reassuring smile of good luck.
Key Research?
Gottesman et al. - Severe mental disorders in offsprings with two psychiatrically ill parents.
Aim?
To examine how vulnerable the children of two parents with mental illness are to developing a mental illness themselves (specifically Schizophrenia and Bipolar Disorder)
Sample?
Denmark national register 2.7million (born before 1997)
opportunity sample
Procedure?
A Cohort study looking at a cohort of a population.
Natural experiment as it looks at two or more naturally occurring groups.
IV - Parental schizophrenia or BD
DV - Diagnosis of any Mental illness in the children.
They were looking at a correlation between the 0/1/2 parents being diagnosed with Schizophrenia or BD and their children with a mental illness diagnosis.
Results?
Schizophrenia:
2 parents - 27.3% for SZ and 67.5% developed a mental illness of some sort.
1 Parent - 7% for SZ and 12% developed a mental illness of some sort.
Bipolar Disorder:
2 parents - 25% for BD, and 44% developed a mental illness of some sort.
1 parent - 4.4% for BD, and 9.2 developed a mental illness of some sort.
Conclusions?
Having both parents with a serious mental illness is associated with a significantly increased risk of developing a mental illness in general. Having one parent lowers the risk. This provides useful information for genetic counselling -> Advises people of their own risks of developing an illness or passing on genetic vulnerability to their children.
Applications?
Electroconvulsive Therapy (ECT)
An alternative medical procedure for treating depression. The procedure involves administering an electric shock for a fraction of a second to the head, inducing a seizure similar to an epileptic seizure. The seizure generally lasts between 15 to 60 seconds. In most cases the shock is administered ti both sides of the head. A typical course of treatment might run for two or three weeks with the ECT being repeated between 6 and 12 times.
ECT is a highly controversial treatment as in its early use the shock given was relatively large and given without anaesthetic or muscle relaxants. This has resulted in patients breaking their bones during the treatment and occasional burns to the brain. However, modern ECT involves smaller shock given for short periods which are given under anaesthetic drugs to paralyse muscles and so prevent broken bones.
Ethical Issues?
Usefulness of Research?
Nature vs Nurture?
