Biological

Seyle's General Adaptation Syndrome
Noticed common set of symptoms in patients despite illness/injury
Suggested that body produces general response to stressor
Response is adaptive as enables body to cope
Several identifiable symptoms= Syndrome 

Stage 1: Alarm
Stressor leads to response
Hypothalamus sends signal to adrenal glands- 'Fight or Flight'

Stage 2: Resistance
Continued stress means body needs to cope
Body maintains normal internal functions but is being depleted of resources

Stage 3: Exhaustion 
Body can no longer maintain normal functioning- immune system
Can result in cardiovascular disorder or depression
 

Psychosurgery
Mentally-disordered behaviour has a physical, biological cause + can be located in the brain
Aims to alleviate severe symptoms by destroying areas of the brain
Used by early humans, 40,000 years ago
Prefrontal Lobotomy developed after aggressive monkeys subdued after removing frontal lobes. 

Prefrontal Lobotomy
Destruction of connections to and from the prefrontal cortex- involved with mood regulation
Relieves patients of distressing thoughts and behaviours
Moniz drilled holes on each side of skull and inserting 'ice pick' to destroy nerve fibres 

Stereotactic Psychosurgery
More precise. Use brain scans (MRI) to locate exact points and sever connections precisely
OCD linked with malfunction in region around thalamus.
In a capsulotomy, surgeons insert probes through top of skull and into capsule, by thalamus
They then heat the tips and burn away tiny portions of tissue.

Deep Brain Stimulation
No tissue destruction. Wires in patients brain, battery pack implanted in chest. Produce high-frquency current that interrupts circuitry involved in e.g. OCD.