Bioloigcal Approach

Localisation of the brain - There are different parts of the brain that have been identified as regulating certain functions. The cerebral cortex covers the surface of the brain which is divided into 4 lobes: frontal lobe, parietal lobe, temporal lobe, occupital lobe. The frontal lobe regulates personality and thinking; the parietal lobe regulates perception; the temporal lobe regulates memory and language; the occupital lobe regulates our vision. Any damage to these areas can result in a change in behaviour. 

Example in psychology - There are specific areas of the brain linked to human behaviour. For example, the limbic system, including the corpus callosum and the amygdala. Problems with these structures have been associated with a lack of inhibition for violence, fearlessness, fear conditioning and an inability to learn the negative consequences of performing a violent act. Raine et al used PET scans to examine and compare the brains of 41 murderers and non-murderers; he found lower activity in these areas. 

Neurotransmitters - The nervous system is made up of neurons which have braches off at the end known as dendrites; these dendrites give the neurons flexibility. When one neuron communicates with another at the synapse, the message can be relayed using a chemical messanger known as neurotransmitters,which is released from the pre-synaptic vesicles in one neuron so that it can stimulate or inhibit another neuron. There are different neurotransmitters that determine behaviour. Dopamine is associated with rewards and schizophrenia; serotonin is associated with sleep and arousal; GABA is associated with a decrease in activity.

Example in psychology - It is suggested that serotonin plays a role in our mood, sleep and appetite. For example, low levels of serotonin has been foudn in those with depression and therefore, antidepressants work by increasing serotonin levels at the postsynaptic receptors to increase their mood. 

Evolutionary influences - The theory of evolution has been used to explain the change in human behaviour over millions of years. Humans have had to adapt to the demands of its individual environments. In addition, the theory of adaptiveness is based on Darwin's theory of natural selection; this is the idea that any genetically determined behaviour than enhances an individual's chances of survivial and reproduction will be passed on to the next generation. 

Example in psychology - Evoluntionary psychology implies that certain fears are adaptive behaviours that helped our ancestors to survive. Seligman proposed the concept of biological preparedness as an inherited predisposition to fear certain types of animals such as snakes. A link was found between animal fears and the likelihood of attack or being contaminated. It was also found that predatory animals and animals linked to disgust naturally caused humans a fear.

Neurotransmitters - It has been found that the chemicals in our brain have a siginificant effect on our emotions and as a result, they influence our perceptions of whom we start relationshps with. To illustrate, as dopamine is associated with pleasure seeking and reward driven behaviour, dopamine will naturally set the goal in finding a partner. This can explain why humans are driven to form relationships: it is because relationships are known to release a hit of dopamine in the reward pathway and give us a natural high. 

Evolutionary influences - An evolutionary theory suggests that individua's will form relationships with those who possess traits that promote successful reproduction. Males will mate more frequently and select women who are more fertile, have healthy smooth skin, glossy hair, red lips and a thin waist; this is because these factors indicate healthiness, youthfulness and signs of physical attraction. Although females will select someone who appaears more fertile and healthy, they are more concerned in finding a partner that will supply for their children in terms of food and shelter. 

Localisations of brain functions - 

Neurotransmitters - 

Evolutionary influences - 

The Medical Model of Mental Illness - the biological appraoch assumes that psychological disorders like anxiety have a physioloigcal cause. The medical model is based on the view that mental illness is the same as a physical illness and so, should be treated in a physical way by altering certain parts of the brain through the various types of psychosurgery. These include prefrontal lobotomy, sterotactic psychosurgery and deep brain stimulation. 
Localisations of brain functions - this assumptions explains that there are different areas of the brain that are responsible for different functions; for example, the frontal lobe is responsible for emotion and impulse. In order to treat a psychological disorders in a physical way, this would involve removing or destroying areas of the brain that are thought to contribute to those psychological problems, such as depression or schizophrenia. The use of prefrontal lobotomy to treat depression involves destorying nerve fibres in the frontal lobe, linked to mood regulation and impulse control. The use of stereotactic psychosurgery is able to reach those deeper brain structures such as the thalamus. 
Neurotransmitters - modern methods of psychosurgery involves stimulating areas of the brain that effect neurotransmitters; low levels of serotonin are responsible for depression and so if this is stimulated, this will increase the serototin leves and improve the patient's mental health. Deep Brain Stimulation allows electrical stimulation to be delievered to specific areas of the brain which in turn triggers a series of reactions that incerase/decrease the levels of neurotransmitters like serotonin, to treat disorders like depression. 

Prefrontal lobotomy - this is a surgical procedure that involves destroying nerve fibres in the frontal lobe, especially areas associated with mood regulation and impulse control. The aim of this is to alleviate some of the symptoms of mental illness. It was thought that by cutting the pathways that carry thoughts through the brain, may cure the patient of their distressing thoughts. Initially,operations were performed on patients with depression, OCD and less successfully with schizophrenia. The severity of the illlness and the danger of the patient was more important than the type of illness.

Prefrontal leucotomy - Moniz developed this this sugrical procedure that involved drilling a hole in the side of the skull and inserting an instrument  that resembled anice pick; later, Moniz refined this tool called a 'leucotome' with a retractable wire loop that could severe nerve fibres. It was hoped that cutting into nerve pathways that carried thoughts, would relieve the patient of their distressing thoughts/behaviours. 

Stereotactic psychosurgery - Instead of removing large sections of the frontal lobe tissue, neurosurgeons use brain scanning techniques like MRI scans, to locate exact points in the brain,before severing connections. This is done under anaesthetic. In OCD, if a circuit linking the brain to deeper structures such as the thalamus appears more active than normal, cingulotomy can surgically interrupt this circuit. A gamma knife can be used to focus beams of radiation at the target site.

Deep Brain Stimulation - DBS involves the surgical placement of thin wires into specific selected brain regions. These electrodes transmit high frequency, continuous electrical impulses that stimulate or inhibit neural activity. The DBS lead is connected to a pacemakerr-like device that is implanted in the chest region which can be turned on and off. The aim of this process is to deliver elctrical stimulation to precise parts of the brain; this triggers a series of reactions that increases or decreases the neurotransmitters. It can be used to treat depression and OCD. DBS differs from the others as it does not permanently destroy brain tissue; it is reversible and causes minimal damage.

Effectiveness of early psychosurgery - Early psychosurgery was not completely effective. It was found that lobotomies had a fatality rate of up to 6/% and also had severe physical side effects such as brain seizure. Comer 2002 found that it significantly affected the patient's intellect and emotional responsiveness

Effectiveness of modern psychosurgery - Modern psychosurgery is difficult to evaluate; the effectiveness of psychosurgery is hard to review seeing as so little operations are carried out. Mayberg 2005 found that DBS was effective for 4 out of 6 patients with severe depression. 

Effectiveness of the appropriateness of psychosurgery - The use of psychosurgery is limited and is rarely used to treat phobias. Although some researchers have called for some controlled trials in its effectiveness in treaing schizophrenia, it it not used as the main treatment. 

Ethical issues in irreversible alteration of brain tissue - As psychosurgery procedure involves the destruction of brain tissue, the results of any operation is irreversible. As a result, this has raised ethical issues as many people believe hat no-one has the right to destroy part of another person, even if it offers a cure. 

Ethical issues in patient's right to give valid consent - Early psychosurgery techniques were used on people in mental asylums and prisons who not neccessarily given their valid consen to the operation. For example, patients with severe depression are not in the right frame of mind to give fully informed consent.

Ethical issues in its irreversible effects - Psychosurgery cannot be reversed and can generate damage to cognitive abilities such as memory and reasoning. Other serious side effects include intellectual and emotional impairment and personality change (vegetable state); prolonged incontinence and epilepsy. Also, following early methods, many patients returned to the community zombie-like and devoid of emotions.Fortunate;y, modern methods have reduced the risk of severe brain damage because they can taregt precise locations in the brain. 

Strength 1 - "It conducts scientific research" - For example scanning methods like PET scans can be used to research links between antidepressant drugs and how they work to treat depression, by increasing serotonin levels.
This is a strength because it means that biological assumptions of behaviour that variables can be measured such as different areas of the brain/hormones. This enables objective, controlled and scientific research to be conducted, ones that demonstrate CAUSE and EFFECT relationships. 

Strength 2 - "It has successful therapeutic applications" - For example, drug treatments are a popular form of treatment and are easy to administer. They have been successful in treating psychotic disorders such as depression, anxiety and schizophrenia.
This is a strength because the biological approach has developed many forms of treatment for mental disorders such as drug therapies and psychosurgery; these therapies have helped many people live normal lives outside of mental hospitals. 

Weakness 1 - "It is a reductionist approach"
For example, this approach suggests that mental illness' such as depression are the result of low levels of the neurotransmitter serotonin.
This is a weakness because by reducing behaviours to a few simple explanations may prevent people from gainning a true understanding of behaviour. For example, the cause of someone's depression may be due to a psychodynamic approach that suggests repressed memories and unresolved conflicts from chilhood or maladaptive learning. In addition, although antidepressants work to increase serotonin levels and relieve symptoms, it does not address the underlying cause of depression and so the symptoms may return due to a simplified explanation. 

Weakness 2 - "It ignores our individual differences" 
For example, research into biological systems has tended to use male particiapnts rather than females, as it is believed that the female hormone cycle may interfere with biological research. This is a weakness because this could portray an untrue picture of behaviour, due to male bias. For instance, research has shown that males tend to respond to stress with a "fight or flight" response whereas females show a "tend or befriend" response. Gender differences are seen in a wide range of species- females nurturing their young (tend) and seeking social support (befriend)