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Psychopathology Learning Table 5: The Biological Approach to Treating OCD
AO1
Drug therapy for mental disorders aims to increase or decrease levels of neurotransmitters in the brain or to increase/decrease their activity. We know that low levels of serotonin are
associated with OCD. Therefore drugs work in various ways to increase the level of serotonin in the brain.
SSRIs
Combining SSRIs with other treatments
Selective Serotonin Reuptake Inhibitors (SSRIs) is a type of antidepressant that is used to tackle the
symptoms of OCD. SSRIs work on the serotonin system in the brain. Serotonin is released by certain
neurons and travels across a synapse. The neurotransmitter chemically conveys the signal from the
presynaptic neuron to the postsynaptic neuron and then it is reabsorbed by the presynaptic neuron
where it is broken down and re-used (see picture).
By preventing the absorption and breakdown of
serotonin SSRIs effectively increase its levels in the
synapse and thus continue to stimulate the
postsynaptic neuron. This compensates for whatever
is wrong with the serotonin system in OCD.
Dosage and other advice vary according to which SSRI
is prescribed. A typical daily dose of Fluoxetine is
20mg although this may be increased if it is not
benefitting the patient. The drug is available as
capsules or liquid. It takes three to four months of
daily use for SSRIs to have much impact on your
system.
Effectiveness
P: One strength of the use of drug therapy to treat OCD
is that there is supportive evidence to show they are
effective.
E: For example, Soomro et al. (2009) reviewed studies
comparing SSRIs to placebos in the treatment of OCD and
concluded that all 17 studies showed significantly better
results for the SSRIs than for the placebo conditions.
E: This is a strength because we can see that the drugs
have a significant impact on the symptoms of OCD.
Typically 70% of patients who use SRRIs see a decline in
symptoms. However, for the other 30%, alternative drug
therapies, or a combination of drug therapy and
psychological treatments would be more effective.
L: As a result, the credibility for drug therapy as a
biological treatment of OCD is increased.
Drugs are often used alongside cognitive behaviour therapy (CBT) to treat OCD. The drugs reduce a
patient’s emotional symptoms, such as feeling anxious or depressed. This means that patients can
engage more effectively with the CBT.
In practice some people respond best to CBT alone whilst others benefit more from drugs like
Fluoxetine. Occasionally other drugs are prescribed alongside SSRIs.
Alternatives to SSRIs
Where an SSRI is not effective after three to four months the dose can be increased (e.g. up to 60mg
a day for Fluoxetine) or it can be combined with other drugs. Sometimes different antidepressants
are tried. Patients respond very differently to different drugs and alternatives work well for some
people and not at all for others.
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Trycyclics (and older type of antidepressant) are sometimes used, such as Clomipramine.
These have the same effect on the serotonin system as SSRIs. Clomipramine has more
sever side-effects than SSRIs so it is generally kept in reserve for patients who do not
respond to SSRIs.
SNRIs (serotonin-noradrenaline reuptake inhibitors). In the last five years a different class
of antidepressant drugs called SNRIs has also been used to treat OCD. These are, like
Clomipramine, as econd line of defence for patients who don’t respond to SSRIs. SNRIs
increase levels of serotonin as well as another different neurotransmitter (noradrenaline).
AO3: Evaluation of the Biological Treatments of OCD
Cost-effective and non-disruptive
Potential side-effects
P: One strength of the use of drug therapy as a treatment P: One issue with using drugs as a treatment for OCD is that
for OCD is that they are cost-effective and non-disruptive. patients may suffer quite severe side-effects.
E: For example, using drug therapy is a much cheaper
E: For example, for those taking Clomipramine, side-effects are
alternative to suing psychological therapies, and is a much more common and often more serious. More than one in ten
easier solution for the patient.
patients suffer erection problems, tremors and weight gain. More
E: This is a strength because using drugs as a treatment
than one in a hundred become aggressive and suffer disruption to
for OCD is better value for a public health system like the
blood pressure and heart rhythm according to research by the
NHS. SSRIs (compared to psychological therapies) are also NHS.
non-disruptive to patient’s lives; you can simply take
E: This is an issue because although the drugs are helpful, and the
drugs until your symptoms decline and not engage with
side-effects are more severe for Clomipramine than other
the hard work in psychological therapies such as CBT and
antidepressants, those patients taking SSRIs could still either not
REBT.
benefit at all from the drug, or still experience some side-effects
L: This means drug therapies as a biological treatment for
including: indigestion, blurred vision and loss of libido (sex drive).
OCD can be seen as a more appropriate method of
L: Because of the risk factor associated with drug therapy, it casts
treatment for some patients.
doubt over the benefit and overall effectiveness of drug therapy as
a biological treatment for OCD.