Explanations of Mental Illness Flashcards
What are the 3 main explanations of mental illness?
The biochemical explanation, the genetic explanation and brain abnormality as an explanation of mental illness.
What does the biochemical explanation see mental illness as?
Sees mental illness as an imbalance of chemicals in the body. For example lack of insulin can lead to diabetes.
Outline the nervous system and how it works in terms of neurotransmitters, neurons, synapse etc.
- Nervous system made up of thousands of nerve cells
- Between 2 cells is a gap called a synapse which allows one cell (pre-synaptic cell) to pass chemicals to another cell (post-synaptic cell)
- Chemicals passing across synapse are called neurotransmitters
- Chemicals cross synapse and transmit electrical signal, and once post-synaptic cell has received chemical, it is taken back to first pre-synaptic cell (called reuptake)
How can biochemistry explain mental illness?
- Sometimes messages between 2 neurons are interrupted
- This could influence availability of certain neurotransmitters meaning we might have too little of something available to use
- This could explain abnormal behaviours
What are the three neurotransmitters which are believed to play a part in mental illness?
Serotonin, Dopamine and Norepinephrine
What mental illness is associated with serotonin?
Depression.
What happens if levels of serotonin are low?
Serotonin won’t get passed along synapse effectively and their message won’t get across before the serotonin gets taken back, therefore it will cause a low mood.
How can you treat an imbalance of serotonin?
Through SSRI drugs (Selective Serotonin Re-uptake Inhibitors) that block the re-uptake so that the neurotransmitters stay in the synapse for longer and have more of an effect.
What mental illness is associated with dopamine?
Schizophrenia.
What effect can illegal substances have on dopamine?
They can increase dopamine so it is unsurprising that drug users can often show symptoms of psychotic disorders.
How can we treat high levels of Dopamine?
Dopamine receptor blockers block the post-synaptic cell receiving the Dopamine, and therefore help to reduce psychotic symptoms.
What is in imbalance of Serotonin and Norepinephrine linked to and why?
Linked to anxiety disorders.
Norepinephrine is released in response to danger.
How can we treat an imbalance of Serotonin and Norepinephrine?
- SNRIs (Serotonin - Norepinephrine Re-uptake Inhibitors)
- They block the re-uptake of serotonin and norepinephrine
What does the genetic explanation of mental illness suggest?
Suggests that certain disorders are passed from one parent to a child through genetic transference.
What did Ohman do in his study of phobias?
- Tried to induce phobias of various object by presenting objects and then an electric shock
- Found people shown images of snakes had greater response to fear than those shown houses and faces
- Measured through galvanic skin response (electrical charge carried through sweat)
- Easiest to condition a fear of the snakes - suggests a biological preparedness
What are monozygotic and dizygotic twins?
- Monozygotic - Identical twins - same genetic make-up and share 100% of genes (come from one egg)
- Diszygotic - Twins who are not identical (2 eggs) and share roughly 50% of their genes
How can twins help us understand the role of genes and the environment?
- As identical twins share 100% of genes, we expect them to share traits
- To measure this we look at concordance rates
- If something is concordant, both twins have it
Outline Gottesman and Shields study and the results.
- They looked at adoption and twin samples to investigate genes and schizophrenia
- Found 58% concordance rates for monozygotic twins - if one twin had it, there is a 58% chance the other will too
- 12% concordance rates for dizygotic twins
What does the brain abnormality explanation see mental illness as?
Sees mental illness as a result of abnormalities within the brain. Abnormality can be in terms of size or in terms of activity.
What are the main ways we can look at brain abnormalities?
Scanning techniques such as MRIs, fMRIs and PET scans.
Outline Brown’s study of schizophrenia.
- Studied 41 patients with schizophrenia, and 29 with an affective disorder
- Found that the brains of patients with schizophrenia were 6% lighter
- Had larger ventricles in the anterior and temporal sections
Outline Weinberger’s study of identical twins.
- Looked at MRI scans to see brain structures of 9 pairs of twins
- The scans showed differences in the prefrontal cortex and the hippocampus volume
- Hard to pinpoint specific brain abnormality associated with mental illness
What did Strakowski find to do with brain abnormality and mood disorders?
- Found that patients with bipolar disorders had differences in their prefrontal, thalamic, hippocampal, amygdala, pallidal and striatal regions compared to a control group
- Amygdala particularly enlarged - part of limbic system (responsible for emotions)
What have studies shown to do with brain abnormality and depression?
Studies shown that patients with depression have a smaller hippocampus than non-depressed people.
What effect can cortisol have on mental health?
Cortisol is a stress hormone and can destroy hippocampal cells, and these cells normally respond to serotonin, meaning it could have a negative effect on mental health.
What does PET scan stand for?
Positron Emission Tomography Scan
What did Baxter find to do with brain activity and abnormality using PET scans?
- Baxter looked at metabolic rates in parts of the brain in patients with OCD before and after treatment
- Changes in behaviour correlated with reduced activity in the right caudate nucleus
What are 3 strengths of the brain abnormality explanation?
- Advanced technology can help identifyn abnormalities
- Can help identify which treatment is needed
- Alleviates blame from individual
What are 3 weaknesses of the brain abnormality explanation?
- Reductionist (ignores other causes)
- Hard to pin-point exact part of brain which is responsible
- May be people who have brain abnormalities but don’t show symptoms of disorders - individual differences