Biological therapies for phobic disorders
In general, psychological techniques for phobic disorders are used; however, biological techniques can be used in a number of situations, to reduce anxiety and allow a person to led a relatively normal life, or in conjunction with psychological therapies so as to allow the patient to reduce anxiety to an extent that they can then take part in some of the psychological techniques.
The two most common types of chemotherapeutic drugs used are anti-anxiety drugs and antidepressants. Both types aim to reduce the anxiety felt by patients around the phobic stimulus and so allow them to lead a relatively normal life. Anti-anxiety drugs include beta-blockers and benzodiazepines. Benzodiazepines aim to reduce anxiety by slowing the central nervous system's activity. They do so by enhancing the activity of a chemical named GABA, or gamma-amino-butyric acid. GABA binds to receptors on the outside of neurones, and in doing so open chloride ion channels on the neurone's membranes. This causes an influx of chloride ions into the neurone, causing hyperpolarisation of the neurone and so making it more difficult for other neurotransmitters to stimulate the neurone. Therefore, the activity of such neurones is reduced, and the person feels more relaxed. Other anti-anxiety drugs include beta-blockers. These drugs restrict the activity of adrenaline and noradrenaline, which are part of the sympathomedullary response to stress. They do so by binding to receptors on the cells of the heart and other parts of the body that are normally stimulated during arousal. This makes it harder for these cells to be stimulated by adrenaline and noradrenaline, and, in doing so, makes the heart beat slower and with less force, and blood vessels do not constrict (i.e. vasoconstriction does not occur). Therefore, arousal decreases, also reducing anxiety.
Antidepressants can also be used to reduce anxiety, the main one of which is SSRI's, or Selective Serotonin Reuptake Inhibitors. SSRI's function by increasing levels of serotonin in synapses around neurones, and so increase the activity of neurones. Choy and Schneier (2008) state that SSRI's are the most commonly prescribed drugs used to treat phobias. However, another type of antidepressant used are MAOI's, or monoamine oxidase inhibitors, and although these are older drugs, Lader and Petursson (1983) state that some patients actually respond better to MAOI's as opposed to SSRI's. Monoamine oxidase is the enzyme that breaks down monoamine neurotransmitters such as dopamine and serotonin, and, so, through inhibiting the action of this enzyme, the number of monoamines present increases, and so increases neurone activity.
As a last resort, psychosurgery can be used to treat phobias. Psychosurgery is a surgical intervention for a behaviour for which no pathological cause can be found. A brain tumour is considered an appropriate reason for psychosurgery because there is a known pathology. The two main types of psychosurgery are a capsulotomy and a cingulotomy, although there are others. A capsulotomy involves functionally removing the capsule, whereas a cingulotomy involves functionally removing the cingulum, both of which are parts of the limbic system associated with emotion. However, psychosurgery is only performed as a last resort if no other options are available due to the irreversible and invasive nature of the process.
There are, however, other types of psychosurgery. One such example is deep brain stimulation, or DBS, which involves placing wires around circuits in a person's brain. These wires are connected to a battery in a person's chest. When the current is on, it disrupts the circuits in a persons' brain. Another reversible, non-invasive process is transcranial magnetic stimulation, or TMS.