psychopathology - OCD Flashcards
what is the genetic explanation for OCD
that the disorder is inherited - genetic analysis has revealed around 230 separate ‘candidate genes’ which are found more frequently with people who have OCD:
- the SERT gene affects reuptake in the serotonin system
- other identified genes include gene 9, COMT gene and 5HT1-D beta gene
- due to the large number of candidate genes OCD appears to be polygenic meaning a predisposition to OCD requires a range of genetic changes
what is the neural explanation for OCD
the neural explanations for OCD includes low serotonin levels, the low level of serotonin is likely due to it being removed to quickly from the synapse before its been able to transmit its signal/influence the postsynaptic cell
what is the worry circuit
a set of brain structures, including the orbitofrontal cortex ( rational decision making ), the basal ganglia system especially the caudate nucleus and the thalamus. communication between these structures in the worry circuit appears to be overreactive in people with OCD resulting in obsessive thinking
what are the strengths of the biological explanation to OCD
- nestadat: dizygotic twins have a 31% concordance rate and monozygotic twins have 68%. MZ and DZ twins grow up sharing similar environments. this suggests that the additional shared DNA is responsible for the increased concordance rate
- the diathesis stress explanation combines a genetic vulnerability to OCD ( diathesis ) with an environmental factor ( stressor ) needed for the disorder to develop. Cromer showed 54% of 265 people with OCD reported at least one traumatic life event
what are the weaknesses of the biological explanation for explaining OCD
- the correlation twin studies does not equal causation. as the concordance rate for MZ twins is 68% , not 100% the level we would expect for an entirely genetically determined psychological feature, there must be some role for the environment
- soomro: a meta analyse demonstrated SSRIS are more effective than placebos suggesting there is a biological aspect to OCD however despite altering levels of serotonin in the synapse within hours these drugs takes weeks to reduce symptoms
what is drug therapy
the primary class of drugs used to control the symptoms of OCD are a group of antidepressant drugs called SSRIS eg. fluoxetine
what are SSRIS
selective serotonin reuptake inhibitors which only influence the select serotonin in the brain, as reuptake inhibitors, they inhibit the reuptake process in the synapse therefore serotonin is still present the synaptic cleft and continues to stimulate the post synaptic neuron. this decreases anxiety by normalising the activity of the worry circuit
what are benzodiazepines
they work by enhancing the neurotransmitter GABA, slowing the CNS and resulting in general relaxation.
what are tricyclics and SNRIS
they increase serotonin and noradrenaline which can be effective when SSRIS fail but because they work on multiple neurotransmitters they tend to have more intense side effects
what are the strengths of the biological approach to treating OCD
- soomro: a meta analysis combining 17 studies comparing SSRIS to placebos. it was found that SSRIS significantly reduce the symptoms of OCD compared to placebos between 6-17 weeks post treatment suggesting drug therapy is effective in short term
- in comparison to psychological therapies such as CBT, drug therapy is relatively ineffective to the NHS and potentially a more convenient for the patient as CBT requires the patient to find time for multiple sessions with a trained therapist
what are the weaknesses of the biological approach to treating OCD
- Goldacre: argues most research studies on drug therapies are conducted by pharmaceutical companies that created them. this means the companies have a financial interest in showing the drugs are effective ( potentially biased results
- many patients prefer CBT: drug therapy can have a range of potential side effects, soomro found nausea, headaches and insomnia were the most common
