biological aaproach to explaining OCD Flashcards
(22 cards)
Lewis
- observed that of his OCD patients, 37% had parents with OCD and 21% had siblings with OCD
= suggests that OCD runs in families although what is probably passed on from one generation to the next is genetic vulnerability not the certainty of OCD - diathesis stress model = certain genes leave some people more likely to develop a mental disorder and some environmental stress is necessary to trigger the condition
Candidate genes
- for example one of the candidate genes is implicated in the transport of serotonin across synapses
Candidate genes
- for example one of the candidate genes is implicated in the transport of serotonin across synapses
OCD is polygenic
- Taylor analysed findings of previous studies and found 230 different genes may be involved in ocd
- genes that have been studied in relation to ocd include those associated with the action of dopamine and serotonin (both neurotransmitters believed to have a role in regulating mood)
Different types of OCD
- one group of genes may cause ocd include those associated one person but a different group of genes may cause the disorder in another
- there is also evidence to suggest that different types of ocd may be the result of particular genetic variations such as hoarding disorder
Role of serotonin
- helps regulate mood
( neurotransmitters are responsible for relaying info from one neuron to the next therefore if a person has low levels of serotonin then normal transmission of mood relevant info does not take place and a person may experience low moods) - some cases of ocd may be explained by reduced functioning of the serotonin system
Decision making systems
- in particular hoarding disorder seem to be associated with impaired decision making
- associated abnormal functioning of lateral of frontal lobe which is responsible for logical thinking and making decisions
Ao3 - biological explanation strength
Research support
Family studies - person with family member diagnosed with ocd is four times as likely to develop it as someone without
Gerald Nestadt
Twin studies
68% of identical mz twins shared ocd as opposed to 31% of non-identical twins dz
Ao3 - biological explanation limitation
Environmental risk factors not accounted for
- ocd is not entirely genetic in origin
- psychologist found that over half the ocd clients in a study had experienced a traumatic event in their past and ocd was more severe in those with traumas
Ao3 - neural explanations strength
Research support - antidepressants
- antidepressants that work purely on serotonin are effective in reducing ocd symptoms supporting view serotonin is involved
- ocd symptoms form part of conditions known to be biological in origin eg Parkinson’s suggesting that biological processes underlie ocd
Ao3 neural explanations - limitation
No unique neural system
- serotonin-ocd link may not be unique to ocd as ppl also experience clinical depression = comorbidity
- depression also involves disruption to action of serotonin
- therefore it could be that serotonin action is disrupted in many people with ocd because they are depressed as well
SSRI
- work on serotonin system in brain
- serotonin is released by presynaptic neuron, travels across synapse to postsynaptic neuron and is then reabsorbed and broken down again by presynaptic neuron
- therefore by preventing reabsorption and breakdown SSRI effectively increase levels of serotonin in synapse and continuously stimulate postsynaptic neuron
- takes 3-4 months to have much impact on symptoms
Combining SSRI with other treatments
- often used alongside CBT
- drugs reduce persons emotional symptoms therefore they can engage more effectively with the therapy
- some people respond best to CBT alone whilst others benefit more when additionally using drugs
Alternatives to SSRI
- where Ssri is not effective after 3-4 months the dose can be increased or combined with other drugs
- tricyclics eg clomipramine acts same way as SSRI on serotonin system but has more severe side effects so is kept for those who do not respond to Ssri
- SNRI = increase levels of serotonin and noradrenaline
Ao3 - biological treatment strength
Evidence of effectiveness
- evidence showing SSRI reduce symptom severity and improve quality of life
- 17 studies comparing SSRI to placebo in treatment of ocd and ALL 17 studies showed better outcomes for SSRI
- symptoms reduce for 70% of ppl taking ssri and remaining 30% can be helped by alternative drugs or combinations with alternative therapies
Counterpoint for evidence of effectiveness in treatment
- evidence to suggest that even if drugs are helpful, they may not be the most effective treatment available
- systematic review of studies carried out and concluded both cognitive and behavioural therapies were more effective than SSRI in treatment of OCD
Drugs may not be optimum treatment
Ao3 - cost effective and non disruptive
- drug treatment is cheap compared to psychological treatments
- therefore good value for public health systems
- non disruptive to patients lives and not forced to engage with hard work of psychological therapy
Drugs have side effects
- significant minority will get no benefit of ssri
- some patients also suffer side effects eg indigestion and blurred vision but they are usually temporary
- more than 1 in 10 suffer from weight gain and erection problems for people taking clomipramine
These factors reduce effectiveness because people stop taking the medication
Unreliable evidence for drug treatments
- although ssri are fairly effective and most side effects are short term all drug treatments have controversy attached
- some psychologists believe that the evidence favouring drug treatments is biased because the research is sponsored by drug companies who do NOT report all of the evidence collected
