Cognitive behavioural therapy for OCD

Aims of CBT in treating OCD

• Controlling compulsions and avoidance - This involves reducing repetitive behaviours and the tendency to avoid situations that trigger obsessions.
• Reducing anxiety from obsessions - By lowering the emotional response to intrusive thoughts, CBT helps decrease their frequency and intensity over time.

These aims work together to break the cycle where obsessions lead to compulsions, which then reinforce the obsessions.

Delivery methods for CBT

CBT can be delivered in various formats: individual, group, or family sessions.

Exposure and response prevention therapy

Exposure and response prevention (ERP) is a specific technique often used within CBT for OCD. It operates on the principle of habituation, which is the process where repeated exposure to a stimulus reduces the emotional response to it over time. This is similar to desensitisation, where something initially exciting or distressing becomes less impactful with familiarity.

How ERP works

ERP assumes that compulsions maintain obsessions by preventing habituation. When a compulsion is performed, it provides short-term anxiety relief, which reinforces the behaviour like a reward, creating an ongoing cycle. Without the compulsion, the obsession would gradually lose its power as the person habituates to it.

The process involves:

1. Gradual exposure - The patient is slowly introduced to the source of their obsession, such as objects related to a fear of contamination or numbers if obsessed with counting.
2. Response prevention - The patient is encouraged to resist performing the compulsion, allowing anxiety to peak and then naturally decrease.
3. Learning new patterns - Through repeated practice, patients develop alternative thoughts and behaviours, reducing the obsession's hold.

This method requires significant effort but leads to a better quality of life by diminishing the control of OCD symptoms.

Breaking the OCD cycle with ERP

CBT, including ERP, challenges the belief that obsessions and compulsions are necessary to prevent harm. Initially, these behaviours develop as coping strategies to feel safer, but they actually increase anxiety and feelings of insecurity. By interrupting this, ERP helps patients realise that not performing compulsions does not lead to catastrophe, gradually extinguishing the cycle.

Drug therapy for OCD

Selective serotonin reuptake inhibitors (SSRIs)

SSRIs are a type of antidepressant medication, such as fluoxetine (commonly known as Prozac), that increase serotonin levels in the brain.

How SSRIs work:

When serotonin is released from the presynaptic neuron (the sending cell) into the synapse (the gap between neurons), it binds to receptors on the postsynaptic neuron (the receiving cell). Any unused serotonin is normally reabsorbed back into the presynaptic neuron through a process called reuptake. SSRIs block this reuptake, leaving more serotonin in the synapse to stimulate the postsynaptic neuron. This leads to improved mood and reduced anxiety, helping to lessen the intensity of obsessions and compulsions.

Tricyclic antidepressants

If SSRIs are ineffective, doctors may prescribe tricyclic antidepressants like clomipramine, an older medication that was among the first used for OCD.

Key features of clomipramine:

• Mechanism - It inhibits serotonin reuptake.
• Effectiveness and side effects - It often works better than other medications but can cause unpleasant side effects.
• Combination therapy - Sometimes combined with an SSRI in treatment.

These drugs improve mood and reduce the anxiety linked to obsessive thoughts.

Benzodiazepines (BZs)

Benzodiazepines, such as diazepam (trade name Valium), are anti-anxiety medications that provide quick relief from the distress caused by OCD symptoms.

How BZs work:

BZs enhance the action of GABA, a neurotransmitter that inhibits neural activity. GABA binds to receptors on neurons, telling them to slow down or stop firing. Approximately 40% of brain neurons respond to GABA, so BZs create a calming effect across the brain, reducing anxiety from obsessive thoughts.