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Explaining Depression - Ellis' ABC Model

AS, A-Level
AQA, Edexcel, OCR, IB

Last updated 22 Mar 2021

Ellis took a different approach from Beck (cognitive triad) to explaining depression and started by explaining what is required for ‘good’ mental health. According to Ellis, good mental health is the result of rational thinking which allows people to be happy and pain free, whereas depression is the result of irrational thinking, which prevents us from being happy and pain free.

Ellis proposed the A-B-C three stage model, to explain how irrational thoughts could lead to depression.

A: Activating Event

An event occurs, for example, you pass a friend in the corridor at school and he/she ignores you, despite the fact you said ‘hello’.

B: Beliefs

Your belief is your interpretation of the event, which can either be rational or irrational.

A rational interpretation of the event might be that your friend is very busy and possibly stressed, and he/she simply didn’t see or hear you.

An irrational interpretation of the event might be that you think your friend dislikes you and never wants to talk to you again.

C: Consequences

According to Ellis, rational beliefs lead to healthy emotional outcomes (for example, I will talk to my friend later and see if he/she is okay), whereas irrational beliefs lead to unhealthy emotional outcomes, including depression (for example, I will ignore my friend and delete their mobile number, as they clearly don’t want to talk to me).

The above example illustrates how an activating event – a friend not greeting you in the corridor – can be rationally or irrationally interpreted. Irrational thinking or interpretations lead to unhealthy outcomes, for example depression, whereas rational and logical thoughts lead to good mental health and happiness.


One strength of the cognitive explanation for depression is its application to therapy. The cognitive ideas have been used to develop effective treatments for depression, including Cognitive Behavioural Therapy (CBT) and Rational Emotive Behaviour Therapy (REBT), which was developed from Ellis’s ABC model. These therapies attempt to identify and challenge negative, irrational thoughts and have been successfully used to treat people with depression, providing further support to the cognitive explanation of depression.

However, one weakness of the cognitive approach is that it does not explain the origins of irrational thoughts and most of the research in this area is correlational. Therefore, we are unable to determine if negative, irrational thoughts cause depression, or whether a person’s depression leads to a negative mindset. Therefore, it is possible that other factors, for example genes and neurotransmitters, are the cause of depression and one of the side effects of depression are negative, irrational thoughts.

Extension: Furthermore, there are alternative explanations which suggest that depression is a biological condition, caused by genes and neurotransmitters. Research has focused on the role of the neurotransmitter serotonin and found lower levels in patients with depression. In addition, drug therapies, including SSRIs (selective serotonin reuptake inhibiters), which increase the level of serotonin, are found to be effective in the treatment of depression, which provide further support for the role of neurotransmitters, in the development of depression.

Finally, there is research evidence which supports the cognitive explanation of depression. Boury et al. (2001) found that patients with depression were more likely to misinterpret information negatively (cognitive bias) and feel hopeless about their future (negative triad), which supports different components of Beck’s theory and the idea that cognitions are involved in depression.

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