The Biological Approach to Treating OCD (11)

Drug therapy (1)

Drug therapy for mental health conditions aims to increase or decrease levels of neurotransmitters in the brain or increase/decrease their activity.

OCD is associated with serotonin, therefore drugs to treat OCD work in various ways to increase the level of serotonin in the brain.

SSRI’s (1)

The standard medical rebate net used to tackle symptoms of OCD involves a particular type of anti-depressant drugs called selective serotonin reuptake inhibitor (SSRI). They work on the serotonin system in the brain.

 

Serotonin is released by certain neurones in the brain, in particular released by the presynaptic neurones and travel across the synapse.

The neurotransmitter chemically converts 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 (2)

thus continue to stimulate the postsynaptic neuron. This means that the serotonin system returns to the usual level of functioning.

Dosage and other advice vary according to which SSRI is prescribed. A typical daily dose of fluoxetine (Prozac) is 10mg although this may be increased if it is not benefiting the person.

The drug is available as capsules are liquid. It can take up to three months of daily use of SSRI’s to have much impact on systems.

Combining SSRI’s with other treatments (1)

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 CBT.

In practice some people respond best to CBT alone, whilst others benefit more when additionally using SSRI’s such as fluoxetine.

Alternatives to SSRI’s (1)

Where an SSRI is not effective after three to four months, the dose can be increased (up to 60mg a day fro fluoxetine) or it can be combined with other drugs.

Sometimes different antidepressants are tried. People response very differently to different drugs and alternatives work well for some people and not at all for others.

Alternatives to SSRI’s (1)

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 SSRI’s.

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 SSRI’s (1)

SNRIs = 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.

SNRI’s increase levels of serotonin as well as another different transmitter - noradrenaline. For SNRI’s regulating noradrenaline levels also brings ease to chronic pain.

A03 - evidence for effectiveness

There is clear evidence to show that SSRI’s reduce symptom severity and improve the quality of life for people with OCD.

 

For example, Soomro reviewed 12 studies (meta analysis) 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 individuals taking SSRIs.

 

For the remaining 30, most can be helped by either alternative drugs or combination of drugs and psychological therapies. 

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

A03 - drawbacks for drug treatments

One limitation of drug treatments for OCD is the serious side-effects.

 

Drugs treatments such as SSRI’s help most people with OCD. However there are often side-effects such as indigestion, blurred vision and loss of sex drive.

 

These side effects are usually temporary, however they can be distressing and for many people the drug effects can bee long lasting.

 

Individuals with OCD may be more sensitive to the dose required to treat their symptoms, which could make side effects more pronounced.

This means that some people have a reduced quality of life as a result of taking drugs and may stop taking them all together, meaning that the drugs cease to be effective.

A03 - radical new drug treatments

There is a degree of patient resistance to conventional drug treatment for OCD because of side-effects.

 

However Lopes and Radillo 2021 case study showed evidence to suggest that people diagnosed with OCD who take the illegal hallucinogenic drug psilocybin (Magic mushrooms) benefit from a reduction in OCD symptoms.

However hallucinogens can lead to highly dangerous behaviour so it may be irresponsible to encourage their use.