biological approach to treating OCD Flashcards
SSRIs
The standard medical treatment used to tackle the symptoms of OCD involves a particular type of antidepressant drug called a selective serotonin reuptake inhibitor (or SSRI for short). SSRIs work on the serotonin system in the brain. Serotonin is released by certain neurons in the brain. In particular it is released by the presynaptic neurons and travels across a synapse (see diagram on the left). 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 reused.
By preventing the reabsorption and breakdown, SSRIs effectively increase levels of serotonin 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 (e.g. brand name Prozac) is 20 mg although this may be increased if it is not benefitting the person. The drug is available as capsules or liquid. It takes three to four months of daily use for SSRis to have much impact on symptoms.
combining SSRIs with other treatments
Drugs are often used alongside cognitive behaviour therapy (CBT) to treat OCD. The drugs reduce a person’s emotional symptoms, such as feeling anxious or depressed.
This means that people with OCD can engage more effectively with the CBT.
In practice some people respond best to CBT alone whilst others benefit more when additionally using 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 60 mg a day for fluoxetine) or it can be combined with other drugs.
Sometimes different antidepressants are tried. People respond very differently to different drugs and alternatives work well for some people and not at all for others.
• Tricyclics (an older type of antidepressant) are sometimes used, such as clomipramine. This acts on various systems including the serotonin system where it has the same effect as SSRIs. Clomipramine has more severe side-effects than SRIs so it is generally kept in reserve for people who do not respond to SSRIs.
• SNRIs (serotonin-noradrenaline reuptake inhibitors) have more recently been used to treat OCD. These are a different class of antidepressant drugs and, like clomipramine, are a second line of defence for people who don’t respond to SSRIs.
SNRIs increase levels of serotonin as well as another different neurotransmitter - noradrenaline.
strength-evidence of effectiveness
One strength of drug treatment for OCD is good evidence for its effectiveness.
There is clear evidence to show that SSRIs reduce symptom severity and improve the quality of life for people with OCD. For example, G. Mustafa Soomro et al. (2009) reviewed 17 studies that compared SSRIs to placebos in the treatment of OCD. All 17 studies showed significantly better outcomes for SSRIs than for the placebo conditions. Typically symptoms reduce for around 70% of people taking SSRIs. For the remaining 30%, most can be helped by either alternative drugs or combinations of drugs and psychological therapies.
This means that drugs appear to be helpful for most people with OCD.
Counterpoint-There is some evidence to suggest that even if drug treatments are helpful for most people with OCD they may not be the most effective treatments available. Petros Skapinakis et al. 2016) carried out a systematic review of outcome studies and concluded that both cognitive and behavioural (exposure) therapies were more effective than SSRIs in the treatment of OCD.
This means that drugs may not be the optimum treatment for OCD.
strength-cost effective and non-disruptive
One further strength of drugs is that they are cost-effective and non-disruptive to peoples lives.
A strength of drug treatments for psychological disorders in general is that they are cheap compared to psychological treatments because many thousands of tablets or liquid doses can be manufactured in the time it takes to conduct one session of a psychological therapy. Using drugs to treat OCD is therefore good value for public health systems like the NHS and represents a good use of limited funds. As compared to psychological therapies, SSRIs are also non-disruptive to people’s lives. If you wish you can simply take drugs until your symptoms decline. This is quite different from psychological therapy which involves time spent attending therapy sessions.
This means that drugs are popular with many people with OCD and their doctors.
limitation-serious side-effects
One limitation of drug treatments for OCD is that drugs can have potentially serious side-effects.
Although drugs such as SSRIs help most people, a small minority will get no benefit.
Some people also experience side-effects such as indigestion, blurred vision and loss of sex drive. These side-effects are usually temporary, however they can be quite distressing for people and for a minority they are long-lasting. For those taking the tricyclic clomipramine, side-effects are more common and can be more serious. For example more than 1 in 10 people experience erection problems and weight gain, 1 in 100 become aggressive and experience heart-related problems.
This means that some people have a reduced quality of life as a result of taking drugs and may stop taking them altogether, meaning the drugs cease to be effective.
extra evaluation-There is always some controversy over the evidence for the effectiveness of drugs. Some psychologists believe that the evidence for drug effectiveness is biased because researchers are sponsored by drug companies and may selectively publish positive outcomes for the drugs their sponsors are selling (Goldacre 2013).
On the other hand, there is a lack of independent studies of drug effectiveness and also research on psychological therapies may be biased. The best evidence available is supportive of the usefulness of drugs for OCD.
