In stress the biological state raises hormone level so psychological state causes the biochemical abnormality.
One theory for depression is all about neurotransmitters serotonin and noradrenaline (happy hormones) and if you have a low amount of these you are more likely to get depressed. Barlow and Durand 1999
The best way to investigate whether mental illness is inherited or not is through family history, or mono-zygotic twins.
Research shows that genetically some people are more at risk than others for developing a mental disorder. E.g. there has been strong evidence that Manic Depression of this disorder being inherited.
The best way to test whether mental illness is inherited is to use monozygotic twins, this is because these have the same DNA. Although you would have to split them apart from birth to iron out environmental issues e.g. upbringing and this is very unethical. It is rare that twins get separated at birth, so there is only a small sample, which people can find results from. Although this sample is small, it has still been theoretically proven that mental illnesses can be biologically influenced.
The biological model says that once the physical cause of a psychological disorder has been identified, a physical therapy is needed to treat the physical problem.
A method of theory is chemotherapy, which involved the use of drugs. The drugs range from
- Minor tranquillisers e.g. anxiety disorders
- Antidepressant e.g. depression disorders
- Major tranquillisers e.g. manic depression, schizophrenia
It is said that these drugs do relive the symptoms, but usually have side effects ranging from fever and nausea, to becoming dependant on the drug, convulsions and even death. Thus making some of the side effects worse than the disorder.
Prozac, the drug taken for depression is effective in 65% to 75% of cases, showing that the drugs will work differently on some people than others. E.g. Tess took Prozac for her manic depression and it totally changed her personality, and therefore changed her life, from good to bad. However a man who had been on the drug for 11 days killed himself and then threw himself of a cliff.
As we see that drugs can work this is seen as reliable enough proof that mental disorders are chemical imbalances.
Some chemicals sometimes affect the functioning of the neurotransmitters giving symptoms of mental disorders. However some psychologists say the chemical imbalance is the effect of the mental disorder instead of the chemical imbalance causing the disorder.
Cromer 1998 said that drugs do not provide a long term solution.
Another method of therapy was electro compulsive therapy (ECT). ECT is the passing of an electrical current through the brain, which causes the brain to have a seizure/and or memory loss. This method is used of cases of depression and used to be given without sedatives, which caused the body to have convulsions. ECT is not commonly used now because of side effects like memory loss. It is 60-70% effective, however is it not even known for how it works, but theory suggests it releases a number of neurotransmitters in the brain - Cromer 1998.
Brain surgery was another method of teatment. Pioneered by Egas Moniz 1937, this treament involved removing sections of the brain. He did prefrontal labotomies, this meaning he cut the fibres running from the frontal brain to other parts of the brain. This was a bad treament because there were major side effects such as apathy, dimished interlectual powers, impared judgement, and death/coma. Moniz was also very unethical about this and used people to test of without their permission, unsurprisingly, he was shot by one of his own patients in the spine.
Gene therapy is another method of helping with mental disorders. The Human Genome Project aims to show the complete genetic make up of humans. In the future individually made genetic engineering may help those at risk from inherited mental disorders. Howvere a problem with this theorpy is that eveidence suggests that it is not only genes that cause mental illness, it is also our environment e.g. upbringing, but genes just increase the chance off getting a mental illness.
The Diatheses Stress Model says it is an interaction between genes and the envoronment that causes mentall illness.
Although there have been a lot of bad points mentioned about this medical model, about it raising ethical concerns, I still feel that is it a very effective and successful model. This is because mental illnesses must be related to our biological make up as for e.g. drugs to work. Therefore mental illnesses must be chemical imbalances in the brain. Also, it had been proven that mental illnesses could be inherited through testing with family history e.g. manic depression and schizophrenia tends to run in the family. No wonder that this is why the biological (medical) model is the most dominant model.