The biological approach to treating OCD

Drug therapy

- This for mental disorders aims to increase or decrease levels of neurotransmitters in the brain or to increase/decrease their activity. Low levels of serotonin are associated with OCD, therefore drugs to treat OCD work in various ways to increase the level of serotonin in the brain

Serotonin

- Released by certain neurons in the brain, particularly by the presynaptic 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 reused

SSRI's

- By preventing the reabsorption and breakdown, these 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 of these is prescribed (e.g. typical daily dose of fluoxetine is 20mg). Available as capsules or liquid. Takes 3-4 months of daily use to have much impact on symptoms

Combining SSRIs with other treatments

- 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. Other drugs can also be prescribed

Alternatives to SSRI's

- When these are not effective after 3 to 4 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. People respond differently to different drugs and some may work well for some people and not at all for others

• E.g. Tricyclics affect the serotonin system in a similar way but produce harsher side effects to are save for people who don’t respond to SSRIs

Alternatives to SSRIs: Tricyclics

- 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 SSRIs so it is generally kept in reserve for people who do not respond to SSRIs

Alternatives to SSRIs: SNRIs (serotonin-noradrenaline reuptake inhibitors)

- More recently been used to treat OCD. Different class of antidepressant drugs, and, like clomipramine, are a second line of defense for people who don't respond to SSRIs. These increase the levels of serotonin as well as another different neurotransmitter- noradrenaline

Evaluation: Strengths

- Evidence for its effectiveness, showing that SSRIs reduce symptom severity and improve the quality of life for people with OCD, e.g. Soomro et al (2009) reviewed 17 studies that compared SSRIs to placebos in the treatment of OCD. All studies showed significantly better outcomes for SSRIs than for the placebo conditions. Symptoms reduce for around 70% of people taking SSRIs, the remaining 30% can be helped with alternative drugs or combinations of drugs and psychological therapies

- This means that drugs appear to be helpful for most people with OCD

Evaluation: Strengths

- Cost-effective and non-disruptive to people's lives. Drug treatments are generally cheap compared to psychological treatment 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 is therefore good value for public health systems and represents a good use of limited funds. SSRIs are also non-disruptive because people can simply take the drugs until their symptoms decline if they wish, psychological therapy involves actually attending each therapy session

- This means that drugs are popular with many people with OCD and their doctors

Evaluation: Weaknesses

- Drugs can have potentially serious side effects. Some people experience side effects such as indigestion, blurred vision, and loss of sex drive. These are usually temporary, however they can be distressing for some and sometimes long-lasting. For those taking clomipramine, side-effects are more common and can be more serious, e.g. some people experience erection problems, weight gain, some become aggressive, some experience heart-related problems

- This means some people have a reduced quality of life as a result of taking drugs and may stop them from taking them altogether, meaning the drugs cease to be effective

Evaluation: Weaknesses

- Controversy over the evidence for the effectiveness of drugs as some psychologists believe it 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 research on psychological therapies may also be biased. The best evidence available is supportive of the usefulness of drugs for OCD