The aim of phychosurgery is to use physical procedures to treat mental disorders such as depression by destroying sections of the brain or by severing nerve connections that connect the frontal lobe to the rest of the brain. In the past it was belived that these would re-generate into healthy connections, however this idea was later proven to be invalid. As well as depression, psychosurgery has also been used for people with severe OCD, bi-polar disorder and schizophrenia.
This first assumption of the biological approach is that behaviour is caused by physical structures in the body ( i.e, the brain, hormones, neurotransmitters). It therefore follws that biological psychologists belive that mental illness have a physical cause and so psychosurgery links to this as it aims to treat mental illness by physically altering brain structure. The biological approach also assumes that different parts of the brain have different functions (i.e., localisation of function) and so psychosurgery links to this as surgery on a specific area will affect a certain behaviour/function (i.e damage to the frontal lobe will affect personality and emotions). This idea underlies psychosurgery as the intention is to disrupt a particular brain function in order to suppress the symptoms of mental illness.
The historical basis for psychosurgery came from the case of Phieas Gage which highlighted that the frontal lobes are linked to personality (but not intelligence or memory). Furthermore, Moinz reported research where monkeys with aggresive tendencies were subdued after frontal lobes removed. In the 1940's and 1950's lobotonies were performed on patients with mental illness to control their aggressive symptoms. For example, with the transorbital lobotomy, the patient is made unconscious via ECT and then a sharp object is inserted into the eye socket into the patient's brain so nerves could be severed between the pre-frontal cortex and the rest of the brain. When the doctor thought that they were at the right stop, they hit the end of the indtrument with a hammer. This did tend to calm patients down, however they became lethargic and socially withdrawn. This form of psychosurgery is no longer used because it was inaccurate, crude and a number of pateints died. More modern methods of psychosurgery involve the use of scanning techniques to locate he exact area of the brain that needs severing. For example, with deep brain stimulation no tissue is destroyed and instead wires are thread through the skull and embedded in the brain. The wires are connected to a battery pack in the patients chest and this produces and adjustable high frequencey current that interrupts brain circuitry involved in OCD, for example. If it doesn't work it can be switched off.
Mayberg et al founsd deep brain stimulation to be effective in reducing the symptons of depression. After stimulation of a small area of the pre-frontal cortex, four out of the six patients got better. This shows that psychosurgery is effective in treating mental illness.