Genetic and neural explanations have been proposed for OCD. Several genes related to serotonin and dopamine transmission have been implicated in increasing vulnerability for OCD. OCD is also polygenic, with evidence that hundreds of genes may be involved. Different types of OCD may result from different genetic variations. Neural explanations suggest low serotonin can impair mood and decision making systems in the frontal lobe. Biological approaches to treatment include selective serotonin reuptake inhibitors (SSRIs) to increase serotonin levels, which studies have shown to be effective in reducing OCD symptoms when combined with CBT. However, drug treatments also have limitations like potential side effects and unreliable evidence.

1. PSYCHOPATHOLOGY

2. Biological approach
to explaining OCD
Genetic explanations:
• Some genes have been identified that may create a
vulnerability for OCD – called candidate genes
• Serotonin genes: 5HTI-D beta are implicated in
transmission of serotonin across synapses
• Dopamine genes have also been found to be
implicated
• Both are neurotransmitters with a role in regulating
mood
• Why might this increase vulnerability for developing
OCD?

3. OCD is polygenic:
• Meaning there are several genes involved
• Taylor et al 2013 found evidence that up to 203 genes
are involved in OCD
There are different types of OCD:
• One group of genes can trigger OCD in one person,
but a different group of genes may cause the disorder
in another – aetiologically heterogeneous
• There is evidence that different types of OCD may
result due to particular genetic variations such as
hoarding and religious obsession

4. Neural
explanations
Low levels of serotonin lowers the mood:
• Neurotransmitters are responsible for relaying information from one
neuron to another
• Is a person has low levels is serotonin then normal transmission of
mood-relevant information does not take place, so mood and other
mental processes are affected
Decision-making systems in the frontal lobe are impaired:
• Some forms of OCD in particular behaviours such as hoarding are
associated with impairments in decision making
• This may be associated with abnormal functioning of the lateral frontal
lobes, which are responsible for logical thinking and making decisions
Parahippocampal gyrus disfunction:
• Some evidence suggests that the parahippocampal gyrus functions
abnormally in people with OCD, this area is associated with processing
unpleasant emotions

5. Evaluation of
explanations
There is good supporting evidence from a variety of sources to suggest people are affected by
genetic makeup when vulnerable to OCD. Nestadt et al 2010 reviewed twin studies, 68% of MZ
twins shared OCD opposed to 31% od DZ twins.This strongly supports genetic influence on OCD
One limitation is that too many candidate genes have been identified, and psychologists have been
unsuccessful at pinning down all the genes involved. One reason for this is it appears several genes
are involved, and each genetic variation only increases risk by a fraction, which makes this
explanation unlikely to be useful in predictive value or application.
There is some supporting evidence for neural explanations of OCD, antidepressants that work purely
on the serotonin system are effective in reducingOCD symptoms which suggests serotonin is
involved in OCD.
A limitation is that people who suffer from OCD are often depressed, this is called co-morbidity, the
depression probably involves a disruption to the serotonin system, which draws the correlation
/causation debate into question.

6. Biological
approach to
treating
OCD
Drug therapy
• Changing the levels of neurotransmitters in the brain
• SSRIs (selective serotonin reuptake inhibitor) prevents
reabsorption and breakdown of serotonin in the brain, increases
levels and compensates for abnormalities in serotonin systems
• Typical dosage of fluoxetine is 20mg (can be increased if needed)
takes 3-4 months of use for symptoms to be affected, can be
increased to 60mg
• Drug therapy is often combined with CBT as they can improve the
effects of this treatment which may have otherwise been
ineffective
• Alternatives to SSRIs areTricyclics hich are older and have the
same effect as SSRIs but with more side effects
• Other alternative is SNRIs – serotonin noradrenaline reuptake
inhibitors – used as second responses if SSRIs don’t work, which
increase levels of serotonin and noradrenaline

7. Evaluation
Drug therapy is effective at tackling OCD symptoms, Soomro et al 2009 reviewed 17 studies comparing SSRIs to placebos in
OCD treatment, all 17 showed netter results for the drug. Effectiveness is greatest when combined with CBT, with a symptom
reduction of 70% for SSRIs, the rest are helped by alternative drugs or CBT.
Drugs are also cost-effective and non-disruptive, as they are cheap compared to psychological treatments, and they are
non-disruptive to a patients life – there’s no commitment to going to therapy sessions etc. Many doctors and patients like
them for these reasons
A limitation is the potential for side-effects, as a small minority of people that take them will get no benefit – side-effects
can be indigestion, blurry vision, loss of sex drive. For those taking Clomipramine (SNRI) side effects can be more serious –
weight gain, erection problems, aggression, BP and HR issues, which all reduce effectiveness as people end up stopping the
use of their medications.
Evidence for drug treatments is also unreliable, as some evidence that supports the use of SSRIs is funded or sponsored by
the companies that produce them who do not report all evidence, Goldacre 2013. They may suppress evidence that does not
support the use of drugs to maximise economic gain
OCD can be caused by other issues aside from biology in some people for example trauma, which would not be treated
through the use of drugs.