Cognitive behavioural therapy for unipolar depression

One specific form of cognitive behavioural therapy (CBT) for unipolar depression is rational emotive therapy (RET), which emphasises replacing irrational beliefs with more realistic ones. Albert Ellis proposed a working model in the 1950s that demonstrates how unreasonable, self-defeating thoughts lead to maladaptive behaviour.

Rational emotive therapy

RET operates on the idea that irrational, self-defeating thoughts lead to maladaptive behaviours and emotional distress. It encourages collaboration between the therapist and client, with the therapist taking an active and directive role. Unlike some therapies that dwell on past events, RET concentrates on the client's current functioning and helps them test and dispute false beliefs.

The ABC model in rational emotive therapy

The ABC model, proposed by Ellis, explains how thoughts influence emotions and behaviours in response to events. It demonstrates that it's not the event itself that causes distress, but the unrealistic interpretation of it.

Components of the ABC model:

• A: Activating event - This is the objective situation or trigger that leads to an emotional response, such as an unpleasant occurrence in daily life (e.g., applying for a job, but receiving a rejection letter).
• B: Beliefs - These are the irrational or negative thoughts about the activating event (e.g., "I was rejected because I am completely incompetent and will never succeed").
• C: Consequences - These are the emotional or behavioural outcomes resulting from the beliefs, such as feelings of despair, low self-esteem, or giving up on future applications.

This model shows that irrational beliefs (B) act as a bridge between the event (A) and the distressing consequences (C). By identifying these beliefs, clients can begin to challenge them.

Challenging irrational beliefs in RET

In RET, clients are encouraged to generate hypotheses about their irrational beliefs and test them through tasks. This behavioural component involves activities that help prove the beliefs wrong, leading to a shift towards more rational thinking.

Steps in developing a dispute-belief system:

1. Identify the irrational belief linked to the activating event.
2. Challenge it with evidence-based reasoning (e.g., "The company received many applications, and rejection doesn't mean I am incompetent, just that another candidate was a better fit for this particular role").
3. Replace the irrational belief with a realistic one, reducing emotional distress.
4. Practice healthy coping strategies to reinforce the new belief system.

As a result, clients develop more adaptive ways of interpreting events, which can alleviate symptoms of unipolar depression over time.

Drug therapies for unipolar depression

Drug therapies for unipolar depression involve medications that typically work by increasing levels of neurotransmitters in the brain, such as serotonin and noradrenaline. These neurotransmitters are often low in people with depression, and their low levels are associated with depressive symptoms. Antidepressants aim to prolong the availability of these chemicals.

Monoamine oxidase inhibitors (MAOIs)

Monoamine oxidase inhibitors (MAOIs) are antidepressants that work by blocking the enzyme monoamine oxidase, which breaks down serotonin and noradrenaline in the synapse. By inhibiting this enzyme, MAOIs increase the availability of these neurotransmitters.

Key features and side effects of MAOIs:

• Effectiveness - They are reasonably effective for reducing depression symptoms.
• Side effects - MAOIs can block monoamine oxidase in the liver, leading to the buildup of tyramine (a substance found in certain foods). High tyramine levels cause dangerous increases in blood pressure.
• Dietary restrictions - Patients must avoid tyramine-rich foods, such as cheese and bananas, to prevent health risks.

Tricyclic antidepressants

Tricyclic antidepressants, named for their three-ring chemical structure, block the reuptake of serotonin and noradrenaline. They do this by blocking reuptake channels on the presynaptic neuron, which leaves more of these neurotransmitters in the synapse for longer.

Key features and side effects of tricyclics:

• Effectiveness - They are generally safer than MAOIs but can impair abilities like driving.
• Side effects - Common issues include dry mouth and constipation, which can affect daily comfort.

Selective serotonin reuptake inhibitors (SSRIs)

Selective serotonin reuptake inhibitors (SSRIs) specifically block the reuptake of serotonin without significantly affecting other neurotransmitters like noradrenaline. This targeted action prolongs serotonin's influence on the postsynaptic neuron. A well-known example is fluoxetine, commonly known as Prozac.

Key features and side effects of SSRIs:

• Effectiveness - They are effective for many patients and harder to overdose on compared to other antidepressants.
• Side effects - Less likely to cause dry mouth or constipation than tricyclics, but they can interact with other medications. In some cases, SSRIs like Prozac may lead to severe effects, such as new suicidal thoughts.