The biological model of abnormality assumes that all mental disorders are caused by physical factors, for example some mental disorders are caused by the dysfunction of neurotransmission, such as too much dopamine in the brain causing schizophrenia, and so the treatments provided by the biological model all aim to address physical problems in the brain that have resulted in abnormal behaviour.
The most widely used form of treatment available under biological therapies is chemotherapy (drugs) with almost 25% of NHS prescriptions being for drugs to treat mental disorders. There are three main types of drugs available to treat mental disorders, the first of these being neuroleptics. Neuroleptics are also referred to as anti-psychotics and are used to treat severe disorders such as schizophrenia. Most neuroleptics block dopamine receptors in the brain, as schizophrenics are found to have more dopamine in the brain than those without schizophrenia. Other neuroleptics simply inhibit the functioning of the hypothalamus which dampens the effect of the dopamine.
Another form of drug available is anti-anxiety drugs, which act as depressants which suppress the autonomic nervous system (ANS). Anti-anxiety drugs help reduce symptoms of general anxiety and are usually used in conjunction with other therapies. They also help to alleviate withdrawal symptoms associated with alcohol or drug addictions. As well as neuroleptics and anti-anxiety drugs there are also anti-depressant drugs which treat depression, OCD and eating disorders, usually by working to help an increase in serotonin.
Another biological treatment is electroconvulsive therapy (ECT). This therapy is declining in use but is still used to treat severe depression if drugs have not worked. ECT is now much safer to perform than in the past as previously ECT could result in broken bones because of the strong muscle spasms it induced in patients. Now however patients are administered a general anaesthetic and muscle relaxants.
As well as this, the shock levels used have also been decreased and so after 5-10 minutes consciousness is regained. There are two main types of ECT. The first is unilateral ECT where electrodes are placed on just one side of the head (usually the non-dominate side of your brain). The second type of ECT is bilateral ECT where electrodes are placed on both sides of the head. After these electrodes have been applied, a current of between 100 and 200 volts is passed for between half a second to 5 seconds. It is suggested that ECT works by causing changes in neurotransmitters causing increased sensitivity to serotonin and an increase in noradrenalin and dopamine.
Benton also proposed that ECT could work in one of three ways; firstly he proposed that ECT may negatively reinforce behaviour through conditioning as ECT could be seen as a punishment. He also proposed that memory loss due to ECT could permit cognitive restructuring and stop negative thinking. Finally he also proposed that ECT could stimulate neurotransmitters to receive more serotonin.
Finally the third therapy available under the biological model is psychosurgery. Psychosurgery is used to treat severe mood disorders, aggression, OCD, eating disorders, anxiety and schizophrenia. Most operations involve destroying some of the nerves of the limbic system which is responsible for control and regulation of emotions, and areas of the brain can be isolated by cutting its connections with the rest of the brain. However this therapy is only ever used as a last resort when chemotherapy and ECT has not worked. There are several forms of psychosurgery, the original being the prefrontal lobotomy developed by Moniz who observed that aggression in chimps could be stopped by removing part of the frontal lobes and severing connections. Moniz claimed a 70% success rate with human patients and was awarded a Nobel Prize for his work. The most up to date form of psychosurgery however is “radio surgery” using a gamma knife, which is a refined surgical technique which causes very precise damage to defined areas.