the biological approach to explaining OCD Flashcards
the biological approach
the emphasis of the biological approach is on how the physical elements of our body may be used to understand behaviour. genetic and neural explanations are forms of the biological approach.
the genetic explanation
individuals inherits specific genes from their parents that are related to the onset of OCD.
the genetic explanation to OCD I
the COMT gene may contribute to OCD, which regulates the production of the neurotransmitter dopamine that has been implicated in OCD.
all genes come in diferent alleles and one allele of the COMT gene has been found to be more common in OCD patients, whereby this variation produces lower activity of the COMT gene and higher levels of dopamine (tukel et al 2013).
the genetic explanation to OCD II
the SERT gene, which affects the transport of the serotonin, creates lower levels of this neurotransmitter. these lower levels are also implicated in OCD.
one study found a mutation of this gene in two unrelated families where 6/7 members had OCD. (ozaki et ak 2003)
diathesis stress model
according to the diathesis stress model, certain genes leave some people more likely to suffer a mental disorder (a diathesis) but it is not certain as some environmental stress is necessary to trigger the condition (stressors).
thus, some people could possess the COMT or SERT gene variations but suffer no ill effects.
the neural explanation
the genes associated with OCD are likely to affect the levels of key neurotransmitters as well as structures of the brain.
the neural explanation to OCD I
dopamine levels are thought to be abnormally high in people with OCD.
- based on animal studies; high doses of drugs that enhance levels of dopamine induce stereotyped movements resembling the compulsive behaviours found in OCD patients.
lower levels of seroronin are associated with OCD.
- this conclusion is based on the fact that antidepressant drugs that increase serotonin activity have been shown to reduce OCD symptoms.
the neural explanation to OCD II
several areas in the frontal lobes of the brain are thought to be abnormal in people with OCD.
when the caudate nucleus is damaged, it fails to suppress minor worry signals and the thalamus is alerted, which in turn sends signals back to the OFC, acting as a worry circuit.
this is supported by PET scans of patients with OCD, taken while their symptoms are active. such scans show heightened activity in the OFC.
evaluation points for genetic and neural expanations, and overall
GENETIC EXPLANATION: good supporting evidence from twin studies.
NEURAL EXPLANATION: supporting evidence; drug treatment
GENERAL: alternative explanations; the biological approach faces strong competition from psychological explanations.
genetic explanation evaluation
good supporting evidence from twin studies.
NESTADT ET AL: reviewed previous twin studies and found that 68% of identical twins shared OCD as opposed to 31% of non-identical twins.
BILLETT ET AL: meta-analysis of 14 twin studies of OCD, found that identical twins (monozygotic MZ) were more than twice as likely to develop OCD if their co-twin had the disorder than was the case for non-identical (dizygotic DZ) twins.
-> clear genetic basis for OCD
neural explanation evaluation
supporting evidence.
eg. some antidepressants work purely on the serotonin system, increasing levels of this neurotransmitter.
-> suggests that serotonin system is involved in OCD.
general explanation evaluation
alternative explanations; the biological approach faces strong competition from psychological explanations.
the two-process model; initial learning occurs when a neutral stimulus i.e. dirt is associaed with anxiety. this association is maintained because the anxiety-provoking stimulus is avoided. thus, an obsession is formed and then a link is learned with compulsive behaviours i.e. handwashing that appear to reduce the anxiety.
supported by the success of a treatment for OCD called exposure and response prevention ERP which is fairly similar to systematic desensitisation.
