chapter 5-biological approaches to obsessive compulsive disorder Flashcards
what does this explanation argue?
- OCD is caused by neural abnormalities in the structure/function of the brain
- partly caused by genes
- assumed to be an illness that can be treated using medical methods
what are the two key areas of the brain that are associated with neural abnormalities?
Basal Ganglia
Orbito Frontal Cortex
what is a basal ganglia?
a group of brain structures at the base of the brain important in emotion and habitat type
what is the orbitofrontal cortex?
the area of frontal lobes and it processes sensory information
what did baxter argue about abnormalities in the loop between the two?
-it may mean that primitive behaviours that are designed to protect us get over activated despite sensory information telling the brain theres no longer a threat
what evidence is there for the OCD and damage to the basal ganglia?
Polak et al 2012
what did polak do?
reported a case of a man who had suffered damage to his basal ganglia after a heart attack
- during the attack his brain was starved of oxygen which resulted in him showing compulsive whistling behaviour
- this was reduced with treatment with a drug that increased the neurotransmitter serotonin
what was the conclusion of polaks research?
symptoms of OCD can be reduced by altering the activity in the circuit between the orbito frontal cortex and the basal ganglia through surgery or brain stimulation
what is a neurotransmitter?
chemicals in the brain that allow messages to be sent between brain sells across synapses
what does it mean when OCD is likely to be polygenic?
it will be linked to many genes not just one
-as many as 230 could be involved in OCD
what would we expect from OCD in twins?
-identical twins share 100% of their genes so if OCD has an genetic component then we would expect that in identical twins both are likely to suffer
what evidence is there for twins and OCD?
Nestadt 2000
- he found that the concordance rate for identical twins was 68% and for non identical it was 31%
- as MZ twins have a higher concordance rate old must have a genetic explanation
what evidence is there for gene mapping?
National institute of Mental Health found OCD was linked to mutation in the human serotonin transporter gene (sort gene)
-this gene is important in explaining how well serotonin is transported across synapses
what does the most common biological treatment for OCD involve the use of?
SSRIS ( specific serotonin re uptake inhibitors )
whats the key example of an SSRI?
Whats the typical treatment lengths?
typical dose?
who can prescribe it?
FLUOXETINE= PROSZAC
3-4 months
20mg a day
by a GP of psychiatrist
