OCD Flashcards
what is OCD
obsessive compulsive disorder
2 elements of compulsive behaviour
compulsions are repetitive
compulsions reduce anxiety
explain compulsions are repetitive
typically sufferers of OCD feel compelled to repeat a behaviour, A common example is hand washing.
explain compulsions reduce anxiety
around 10% of sufferers from OCD experience compulsions alone. However, the vast majority of compulsive behaviours are performed in an attempt to manage the anxiety produced by obsessions. eg hand washing is a response to the obsessive fear of germs
avoidance as a behavioural characteristic
they attempt to reduce anxiety by keeping away from situations that trigger it. For example coming in to contact with germs.
3 emotional characteristic of OCD
anxiety, accompanying depression, guilt
cognitive characteristics
obsessive thoughts
GENETIC EXPLANATIONS:
what are the candidate genes which create vulnerability for OCD
COMT gene and SERT gene
what does the COMT gene do
the COMT gene regulates the neurotransmitter dopamine. One variation of the COMT gene results in higher levels of dopamine, which is implicated in OCD
what does the SERT gene do
the SERT gene is linked to the neurotransmitter serotonin and affects the transport of serotonin causing lower levels of serotonin which is associated with OCD.
explain how OCD is polygenic
Taylor discovered that there are several different genes (up to 230) involved in OCD. OCD is aetiolically heterogenous which means that the origin of OCD has many different causes.
one strength of the biological explanation for OCD (family studies)
Lewis examined patients of OCD.
37% had parents with OCD and 21% had siblings with OCD
strength of biological approach (twin studies)
Nestadt et al. reveiwed twin studies and found that 68% of identical twins (MZ) experience OCD and 31% of non-identical twins (DZ) experience OCD. Suggests a strong genetic component. However, not 100% so there must be other factors involved.
weakness of biological approach (diathesis stress model)
The diathesis stress model suggests that there are also environmental factors involved in triggering the risk of developing OCD. Researcher found that over half of OCD patients had a traumatic event in their past, and OCD was more severe in those who had experienced multiple traumatic events.
NEURAL EXPLANATIONS:
what do neural explanations focus on
the role of neurotransmitter such as serotonin and dopamine as well as brain structure
what does serotonin do
regulate mood
explain the role of serotonin
neurotransmitters are responsible for relaying information from one neuron to another. if a person has low levels of serotonin then normal transmission of mood-relevant information does not take place and mood is affected.
explain the role of the orbifrontal cortex
PET scans have found higher activity in the orbifrontal cortex in patients with OCD. Suggests the hieghtneed activity increases the conversion of sensory information to actions (behaviours) which results in compulsions. The increased activity causes patients difficulty switching off or ignoring impulses.
basal ganglia
it is a brain structure involved in multiple processes, including the coordination of movement.
research support for neural explanation
there is evidence to support the role of antidepressants working on the serotonin system, increasing levels of the neurotransmitter. These drugs are effective in reducing the OCD symptoms.
TREATING OCD:
what does drug Therapy aim to do
to increase or decrease levels of neurotransmitters in the brain
what does serotonin do
Selective serotonin reuptake inhibitors (SSRI’s) work on the serotonin system in the brain. When serotonin is released from the pre-synaptic cell into the synapse, it travels to the receptor sites on the post-synaptic neuron. serotonin which is not absorbed in to the post synaptic neuron is reabsorbed into the sending cell (pre-synaptic neuron)
how do SSRI’s work
SSRI’s increase the level of serotonin available in the synapse by preventing it from being reabsorbed into the sending cell. This increases levels of serotonin in the synapse and results in more serotonin being received by the receiving cell (post-synaptic neuron)
how do anti-anxiety drugs help OCD sufferers.
BZ’s work by enhancing the neurotransmitter GABA. GABA tells neurons in the brain to ‘stop firing’ and around 40% of the neurons in the brain respond to GABA. This means BZ’s have a general quietening influence on the brain and consequently reduce anxiety, which is experienced as a result of obsessive thoughts.
