Explaining OCD: Biological Approach Flashcards
biological explanations for OCD
genetic explanation
neural explanation
outline the genetic explanation for OCD
One explanation of OCD is that it is genetically inherited and runs in families.
However, what is probably passed on from one generation to the next is genetic vulnerability not the certainty of OCD.
According to the diathesis-stress model certain genes leave some people more likely to suffer a mental disorder but it is not certain - some environmental stress (experience) is needed to ‘trigger’ the condition.
Researchers have identified genes which create this vulnerability for OCD, called ‘candidate genes’, for example gene 9.
However, like many conditions, OCD seems to be ‘polygenic’ which means it is not caused by a single gene but that several genes are involved.
Some estimates suggest as many as 230 different genes may be involved and different types of OCD may be caused by different combinations of these genes.
Family studies indicate a higher percentage of first degree relatives have the disorder (10%) compared to the prevalence rate (2%).
outline the neural explanation for OCD
The genes associated with OCD are likely to affect the levels of key neurotransmitters (chemical messengers) as well as structures in the brain. These are neural explanations.
One neural explanation of OCD concerns the role of the neurotransmitter, serotonin which is believed to help regulate mood.
If a person has low serotonin transmission then normal transmission of mood-relevant information across the synapse does not take place and the person’s mood; and sometimes other mental processes, are affected.
Serotonin may be’removed too quickly before it has transmitted its signal.
Other neural explanations of OCD refer to structural deficits in the brain.
Some cases of OCD seem to be associated with impaired decision-making.
This may be linked with abnormal functioning of the lateral frontal lobes (responsible for thinking and decision making).
Further structural deficits that have been found in cases of OCD include abnormal functioning in the parahippocampal gyrus, which processes unpleasant emotions.
This is thought to be linked with the development of anxiety, obessions and irrational beliefs.
Research has also found cases of hyperactivity in the basal ganglia, which is an area of the brain linked to repetitive actions.
Hyperactivity in this area is thought to be linked with the compulsions that OCD sufferers experience.
Evaluation: genetic/neural explanations of OCD
- STRENGTHS
NEURAL:
P: ‘scientific’
E: focuses on observable, measurable biological features
E: eg, many modern techniques such as MRI brain scans have revealed that some OCD patients appear to have brain abnormalities such as a loss of tissue in the frontal lobes of the brain which could indicate brain abnormality plays a part in the disorder
L: enables the approach to be empirically tested
GENETIC:
P: twin studies have supported the genetic explanation of OCD
E: Evidence for this comes from Nestadt et al (2010)
E: reviewed previous twin studies and found that 68% of monozygotic (MZ) twins shared OCD as opposed to 31% of dizygotic (DZ) twins
L: supports the idea that the more genes we share with a sufferer, the more likely we are to develop OCD too
NEURAL:
P: practical applications:
E: drug therapies which aim to correct neurotransmitter imbalances in the brain have been shown to be effective in treating OCD.
E: Evidence to support this comes from Soomro et al (2009) who found that SSRIs were significantly more effective than placebos in treating OCD
L: useful in developing treatments that are effective in addressing OCD
E: However, not all patients respond to drug therapy which casts doubt on the
explanations validity
P: seen as ‘humane’ due to being biologically determinist
E: suggests our behaviour is controlled by neurotransmitter imbalances or genes
E: For example, if a person develops OCD, this may have been ‘programmed’ by their genes and neurochemistry and there is nothing the person can do to avoid it
L: removes the blame hom the sufferer
Evaluation: genetic/neural explanations of OCD
- LIMITATIONS
P: biologically reductionist
E: reduces the complex issue of mental health down to its most basic parts such as genes, and ignores the role that the environment may play
E: eg, although concordance rates are often found to be higher in MZ than DZ twins for OCD, the fact concordance rates are not 100% in MZ twins suggests other factors must also play a part
L: biological approach to OCD may be too simplistic
E: BUT, this may support the idea that the diathesis-stress model of OCD may
be more effective than a purely genetic explanation as this acknowledges that both genes and the environmental play a role in OCD
P: issue of causation
E: Although neurochemical imbalances and structural abnormalities have been found in numerous cases of OCD, it is difficult to establish whether these are causes of OCD or simply symptoms of the disorder
E: research into cases of OCD tends to be retrospective, so it’s difficult to build up a before and after picture in terms of levels of neurotransmitters and brain structure
L: difficult to establish if neural impairments actually cause OCD or the other way round, thus casting doubt on the validity of the explanation
