psychopathology - OCD Flashcards
Genetic explanation to OCD
Genes may create a vulnerability to OCD. There is evidence that OCD runs in families.
Lewis (1936) found that 37% of patients with OCD had parents with the disorder. The diathesis-stress model suggests that, along with this vulnerability, the environment may trigger OCD.
There are many candidate genes involved in OCD (for example, those involved in the serotonin and dopamine systems), and it is polygenic: several genes are involved.
Evaluation of genetic OCD explanation - twins
Supporting evidence from Nestadt et al showed that 68% of identical twins were both diagnosed with OCD, compared to 31% of non-identical twins, suggesting there is a genetic basis.
However, since there is not a 100% concordance rate, there must be other factors involved, providing support for the diathesis-stress model.
Evaluation of genetic OCD explanation - candidate genes
There are too many candidate genes for OCD- potentially hundreds. This means that finding a definitive genetic cause is very unlikely, reducing the usefulness of this explanation.
Neural explanation of OCD
Low levels of serotonin (a neurotransmitter) leads to impaired transmission of mood-relevant information, leading to a lowered mood.
Low levels of serotonin are also linked to obsessive thoughts.
Low levels of dopamine linked to the reward system.
Abnormal frontal lobe functioning leads to impaired decision-making, leading to symptoms of OCD.
Evaluation of neural OCD explanation - serotonin
Supporting evidence from antidepressant studies shows that increasing serotonin levels reduces OCD symptoms, suggesting serotonin has a role in the development of OCD
Evaluation of neural OCD explanation - cause-effect
The cause-effect relationship not known- it could be that changed in the brain are a result of OCD, rather than causing it in the first place. This weakens the neural explanation.
Describe drug therapies in OCD
SSRIs (selective serotonin reuptake inhibitors) are the most commonly prescribed drugs for OCD. These work by blocking the transporter mechanism that re-absorbs serotonin into the presynaptic cell after it has fired. As a result, more serotonin is left in the synapse to be absorbed by the post synaptic cells. Dosages vary with the patient, and it takes 3-4 months for benefits to show. An example of an SSRI is Fluoxetine. Often SSRIs will be combined with CBT.
Evaluate drug therapies as a treatment for OCD - Soomro
One strength of drug therapy for OCD was shown by Soomro et al (2009). In this study, it was found that SSRIs were significantly better than placebos (fake drugs) at reducing OCD symptoms, showing that the drugs are effective.
Evaluate drug therapies as a treatment for OCD - real life
Compared to psychological treatments, drug therapy is easy and non-disruptive, as the patient just needs to take a pill rather than undergoing lengthy therapy sessions. This is a strength because the treatment suits people no matter what their lifestyle, job, and so on.
Evaluate drug therapies as a treatment for OCD - side effects
A weakness of drugs is that they can have side effects, for example indigestion, loss of sex drive, blurred vision, weight gain and aggression. This weakens the use of drugs because patients may be less willing to take them, therefore their OCD symptoms will return.
