Psychopathology

The Biological Approach to Explaining OCD

Genetic Explanation
Genes are involved in individual vulnerability to OCD.
Nestadt et al (2010) - 68% of identical twins shared OCD, as opposed to 31% of non-identical twins.
OCD seems to be polygenic - not caused by one single gene but several genes are involved.
Taylor (2013) - there are up to 230 genes involvement: possible candicate genes:
5HT1-D gene - transport serotonin across synapse.
SERT gene - regulating serotonin, neurotransmitter > facilitates messages.
COMT gene - regulates production of dopamine.
If concordance rate for MZ twins is not 100% this suggest - other factors must be involved for cause of OCD

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Neural Explanation
The perception of OCD as a result from abnormality functioning brain mechanism.
OCD seems to be associated with impaired decision making which in turn may be associated with abnormal functioning of the lateral frontal lobe of the brain.
Neurotransmitter are responsible for relaying information from one neuron to another.
If a person has low levels of serotonin then normal transmission of mood-relevant information does not take place - mental process may be affected.
The left paraphippocampal gyrus - associated with processing unpleasant emotions, functions abnormally in OCD.

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Good supporting evidence
Nesdath et al - 68% identical twins = OCD. 31% non identical twins =OCD.
Some people are vulnerable to OCD as a result of their genetic make up.
It strongly suggest that there is a genetic influence on OCD.
Too many gene candidate involved
Several genes are onvolved and that each genetic variation only increases the risk of OCD by a fraction.
Genetic explanation is unlikely to eve be very useful because it provides little predictive value.
It isn't completely genetic.
Environmental factor are involved can trigger or increase the risk of developing OCD.
Cromer et al (2007) - OCD patients had a traumatic event in the past, OCD was more severe in those with more than one trauma.

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Drug Therapy - aims to increase/decrease levels of neurotransmitter i the brain to increase/decrease their activity.
Drugs work in various ways to increase the level of serotonin in the brain.
SSRIs - work on the serotonin system in the brain. Serotonin released by certain neurons in the brain.
Neurotransmitter chemically conveys the signal from the presynaptic neuron to the postsynaptic neuron - it is reabsorbed by the presynaptic neuron where it is broken down and re-used.
Prevention of re-absorbtion and breakdown of serotonin SSRIs effectively increase its levels in the synapse.
Compensates for whatever is wrong with the serotonin system in OCD.
Takes 3-4 months of daily use of SSRIs to have impact on symptoms.

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Combination of SSRIs with CBT
Drugs reduce patients's emotional symptoms such as anxious or depressed.
Patients can engage more effectively with the CBT
Alternative to SSRI = SNRIs
Serotonin-noradrenaline reuptaake inhibitors.
Clomipramine - second line of defence for patients who dont's respond to SSRIs.
SNRIs increase levels of serotonin as well as another different neurotrasmitter - noradrenaline.
SNRI has also been used to treat OCD in the last 5 years
Ha the same effect on the serotonin system as SSRIs.

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Drug therapy tuckles OCD symptoms.
Clear evidence that SSRIs reduces the severity of OCD symptoms = improving the quality of life for OCD pateitns.
Soomro et al (2009) - compared SSRIs to placebos in treatment of OCD. = all 17 studies showed significantly better results for SSRIs than Placebos conditions.
SSRI's combined with a psychological treatment (CBT) is very effective.
Cost effectve and non-distruptive
Drug treatments are cheap compared to psychological treatments.
SSRIs are non-disruptive to patient's lives as it declines sumptoms and does not engage with hard wok of psychological therapy.
Many doctors and patients prefers drug treatments for these reasons.

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Drugs can have side effects
Side effects such as indigestion, blurred vision and loss of sex drive are usually temporary.
Patients taking Clomipramine have common side effects = becoming aggressive and suffer disruption to blood pressure and heart rhythm.
One OCD pateitns stop taking medication, it can have factors which reduces effectiveness of the drug therap.
In some cases, psychological therapies is better than drug therapy.
Some cases, OCD follow trauma
OCD is widely believed to be biological in origin - standard of treatment should be biological
It is acknowledge that OCD can have a range of other causes in some cases, a response to a traumatic life event.
If OCD is caused by trauma, drug treatment may not be appropriate.

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