PAPER 1 - PSYCHOPATHOLOGY - biological approach to explaining & treating OCD Flashcards
what is the fundamental belief of the biological apporach?
behaviour is a result of genetics and naurotransmitters
what is the role o the COMT gene in the development of OCD?
COMT regulates production of dopamine which has been implicated in OCD & this variation leads to lower activity of the COMT gene and high levels of dopamine
- more commonly found in those with OCD
what is the role of the SERT gene?
- involved in transport of seratonin-mutation of this gene
- leads to lower levels of serotonin
- Ozaki (2003) found mutation of this gene in 2 unrelated families, 6 of 7 members had OCD
how is the role of genetics investigated?
family studies - especially MZ twins
what does diathesis stress suggest?
- genes create genetic vulnerability to mental disorders (diathesis) but other factors (stressors) influence development of a disorder
- simple link between one gene and a complex disorder like OCD is unlikely
how is dopamine associated with OCD?
- dopamine affects motivation and ‘drive’
- dopamine levels are thought to be abnormally high in people with OCD
- high levels of drugs that enhance levels of dopamine induce stereotyped movements - showing behaviours found in OCD
how is serotonin associated with OCD?
- lower levels of serotonin are associated with OCD, based on antidepressant drugs that increase serotonin activity decrease OCD symptoms
- antidepressants with less of an effect on serotonin don’t reduce OCD symptoms
what is the worry circuit (abnormal brain circuit) in the brain?
- several areas in frontal lobes of the brain are thought to be abnormal in people with OCD
- caudate nucleus normally suppresses signals from orbitofrontal cortex (OFC)
OFC sends signals to thalamus about things that are worrying - if caudate nucleus is damaged it cant suppress minor ‘worry’ signals so acts as a worry circuit
evaluation for explaining OCD - what is the research from family studies?
- Nestadt (2003) found people with first degree relative with OCD had 5x greater risk of developing it
- twin studies show MZ twin twice as likely to develop OCD if twin had it compared to DZ twins
- HOWEVER concordance rates are never 100% which means environmental factors must play a role too (diathesis-stress)
evaluation for explaining OCD - what is the research support for genes and OFC?
- many studies demonstrate genetic link to abnormal levels of neurotransmitters
- researchers used MRI to produce images of brain activity in OCD patients and immediate family members
- OCD patients & close relatives had reduced grey matter in key regions of the brain including OFC
- supports anatomical differences are inherited and may lead to OCD
evaluation for explaining OCD - what is the real world application for explaining OCD?
- mapping of human genome led to hope that specific genes could be linked to particular mental and physical disorders
- it gives opportunities for early intervention like termination of eggs however that raises ethical issues
- presumes there is a simple relationships between a disorder and genes (unlikely) so mapping of genome is controversial
what are SSRIs? (drug therapy)
- type of antidepressant (Selective Serotonin Reuptake Inhibitors)
- lower levels of serotonin associated with OCD
- inhibit reabsorption of serotonin after its been received by receptor cells
- less addictive
what are tricyclics? (drug therapy)
- type of antidepressant
- primarily used for OCD
- blocks transporter mechanism that absorbs serotonin & noradrenaline
- both neurotransmitters are left in synapse to prolong activity
- treat more than one neurotransmittter
what are benzodiazapines? (drug therapy)
- type of anti-anxiety drug
- slows activity of CNS by enhancing action of GABA (calming neurotransmitter)
- GABA receptors increase flow of chloride ions that make it harder for neuron to be stimulated by other neurotransmitters
- individuals then feel more relaxed
evaluation for treating OCD - what is the evidence for effectiveness of drug therapy?
- lots of evidence for effectiveness
- randomised control trial is used to compare effectiveness of drugs vs placebo (random allocation to drugs)
- researchers reviewed 17 studies of use of SSRIs with OCD patients, found them to be more effective than placebos - reduced symptoms of OCD up to 3 months after treatment
- studies only show short term benefits
evaluation for treating OCD - what are the advantages of drug therapy to a) the individual? b) the health service?
a) requires little input (less time & effort) - contrasting to CBT
b) requires little monitoring & cheaper than psychological treatments
evaluation for treating OCD - what are the possible side effects of drug treatment?
- nausea, headache, insomnia - common side effects of SSRIs and can make patient stop taking the drug
- tricyclic antidepressants can cause hallucinations, irregular heart beat
- benzodiazapines can cause aggression & long term impaired memory
evaluation for treating OCD - what is the possible advantage to drug treatment compared to CBT?
- not long lasting cure for OCD
- researchers found patients relapse within a few weeks if medication stopped
evaluation for treating OCD - what is meant by publication bias?
- publishing overly positive results
- Turner et al found evidence for publication bias towards studies that show positive outcome of antidepressant treatment
- leads to doctors making inappropriate treatment decisions
