Everyone experiences difficult emotions. You might feel disappointed after receiving a poor grade, upset after an argument with a friend, or worried about an important examination. These feelings are a normal part of life and usually change as circumstances change.
Depression is different. It is a mental health condition that can involve persistent low mood, loss of interest or pleasure, changes in motivation, difficulties concentrating and negative patterns of thinking. It can affect how someone sees themselves, other people and the future, as well as how they behave in everyday life.
For psychologists, depression raises an important question: why does it develop, and why can negative thoughts and behaviours sometimes become so difficult to break?
There is no single explanation that accounts for every experience of depression. Biological, psychological and social factors can all be relevant. In GCSE Psychology, however, one particularly important approach is the cognitive approach, which focuses on the role of thoughts and beliefs.
Two psychologists are especially important here: Aaron Beck and Albert Ellis. Beck developed the idea of the negative triad, while Ellis proposed the ABC model and focused on irrational beliefs.
Understanding these theories also helps us understand Cognitive Behavioural Therapy (CBT), one of the psychological approaches used to treat depression.
What is depression?
Depression is more than simply feeling sad. A person experiencing depression may experience a combination of emotional, cognitive, behavioural and physical changes. They might lose interest in activities they previously enjoyed, withdraw from other people, struggle with motivation or find it difficult to concentrate.
Some people may experience changes in appetite or sleep, while others may feel exhausted even when they have not done much physically.
Importantly, depression does not look exactly the same in everyone. One person may become noticeably withdrawn, while another may continue attending school or work and appear outwardly fine while struggling internally.
This is why psychological explanations focus on patterns rather than assuming that every person experiences depression in exactly the same way.
For GCSE Psychology, one of the most important questions is how thinking patterns can contribute to the development and maintenance of depression.
The cognitive approach
The cognitive approach focuses on mental processes such as thoughts, beliefs, interpretations, attention and memory. When applied to depression, cognitive psychologists argue that the way people interpret events can influence how they feel and behave.
Consider two students who both receive the same disappointing examination result.
The first student thinks:
“I didn't do as well as I hoped. I'll look at my mistakes and work on them before the next exam.”
The second student thinks:
“I'm stupid. I'll never succeed. There's no point trying anymore.”
The event is identical but the interpretation is different.
According to cognitive explanations, this difference in thinking can contribute to differences in emotional and behavioural responses.
The cognitive approach therefore asks us to look beyond what happened and examine what the person believes the event means.
Beck's cognitive explanation of depression
Psychologist Aaron Beck developed an influential cognitive explanation of depression. Beck argued that people experiencing depression can develop systematic negative patterns of thinking.
One of his most important concepts is the negative triad.
The negative triad consists of negative views about: the self, the world and the future.
These three patterns can interact and reinforce one another.
Negative views of the self
The first part of Beck's triad involves how a person sees themselves.
Someone experiencing depression may develop thoughts such as:
“I'm worthless.”
“I'm not good enough.”
“Everything is my fault.”
A setback that might normally be interpreted as temporary can instead become evidence of a broader negative belief about the person's identity.
For example, a student who performs badly in one examination might think:
“I failed because I'm not intelligent.”
The student is no longer evaluating one examination result. They are using the result to make a much broader judgement about themselves.
Negative views of the world
The second part involves a negative interpretation of the world around the person. They may see other people as critical, hostile or uninterested in them. They may believe that life is unfair or that there are very few opportunities available to them.
Again, ordinary experiences can be interpreted negatively.
For example, if a friend does not reply to a message, a person might think:
“They're busy.”
But someone experiencing a strong negative thinking pattern might interpret the same event as:
“They don't like me.”
The situation has not changed. yet the interpretation has not.
Negative views of the future
The final part of the triad concerns expectations about what will happen next.
A person may believe that their circumstances will never improve.
They might think:
“Nothing is going to get better.”
“I'll always feel like this.”
“There is no point trying.”
This can reduce motivation.
If someone genuinely believes that their future cannot improve, they may see little reason to make changes in the present.
This can contribute to a cycle in which negative expectations influence behaviour, and the resulting behaviour reinforces the original beliefs.
The negative triad in everyday life
Imagine a student receives a disappointing GCSE mock examination result.
They think:
Self: “I'm terrible at this subject.”
World: “Everyone else is better than me.”
Future: “I'm going to fail the real examination too.”
The three thoughts reinforce each other because the student believes they are incapable, they may become less motivated to revise. Because they expect failure, they may avoid challenging work. The lack of revision may then lead to another poor result and by that, that result appears to confirm the original belief:
“I knew I couldn't do it.”
This illustrates how cognitive and behavioural factors can interact.
Negative automatic thoughts
Another important idea associated with cognitive explanations is negative automatic thoughts. These are thoughts that can appear quickly and automatically in response to situations.
A person may not consciously decide:
“I am now going to interpret this event negatively.”
The thought simply appears.
For example, a student sees a teacher return an assignment.
Before even looking at the grade, they might think:
“I've definitely failed.”
That thought could immediately produce anxiety or disappointment.
Cognitive approaches aim to help people recognise these patterns rather than automatically accepting every thought as accurate.
Ellis's ABC model
Another major cognitive explanation of depression comes from Albert Ellis. Ellis developed the ABC model, which suggests that emotional consequences are influenced by the beliefs people hold about events.
The three components are:
A — Activating event
B — Belief
C — Consequence
Let's look at each one.
A — Activating event
The activating event is what happens.
For example: A student receives a low examination grade.
The event itself is unpleasant, but Ellis argued that the event does not automatically determine the emotional response. He argued that Something happens between the event and the consequence.
That is the person's belief about what happened.
B — Belief
The belief is the person's interpretation of the activating event.
One student might think:
“This result isn't good, but I can improve.”
Another might think:
“I must always succeed. If I fail, it means I'm worthless.”
These beliefs are very different. According to Ellis, rigid and unrealistic beliefs can contribute to emotional problems.
C — Consequence
The consequence is the emotional and behavioural response that follows the belief.
The first student might feel disappointed but continue studying.
The second student might feel overwhelmed, lose motivation and avoid studying altogether.
The important point is that A does not automatically produce C.
The belief in B influences the consequence.
Ellis and irrational beliefs
Ellis argued that some people develop irrational beliefs that place unrealistic demands on themselves or other people.
These beliefs can involve words such as: must, should, always or never.
For example:
“I must be successful at everything I do.”
“Everyone must like me.”
“I should never make mistakes.”
“If something goes wrong, it means I'm a failure.”
These beliefs create extremely high standards. If a person believes they must succeed every time, even an ordinary mistake can feel catastrophic.
What is “musturbation”?
Ellis used the unusual term musturbation to describe rigid demands that people place on themselves, other people or the world.
The term is memorable, which is one reason it often appears in psychology revision materials.
Examples include:
“I must always be successful.”
“People must treat me fairly.”
“My life must go exactly as I planned.”
The problem is not having goals or expectations.
The problem is treating these expectations as absolute requirements.
When reality inevitably fails to match them, the person may experience significant emotional distress.
Ellis believed that challenging these irrational beliefs could help people develop more flexible ways of thinking.
Beck and Ellis: what is the difference?
Beck and Ellis both developed cognitive explanations, but they approached depression differently.
Beck focused on negative thinking patterns, particularly the negative triad involving the self, world and future.
Ellis focused more heavily on irrational beliefs and the way people interpret activating events.
Both approaches share a central principle: Our interpretation of events can influence our emotional and behavioural responses.
This is important because changing the way a person interprets an experience may change how they respond to it.
How can depression become a cycle?
One of the most useful ways to understand cognitive explanations is to think about depression as a cycle.
Imagine someone believes:
“I'm going to fail.”
Because they believe failure is inevitable, they stop putting effort into their work.
They revise less. They avoid difficult tasks. Their performance becomes worse. The poor result then appears to confirm their original belief.
The cycle becomes: Negative belief → reduced motivation → negative behaviour → poor outcome → stronger negative belief.
Breaking this cycle is one of the reasons psychological treatments for depression often address both thoughts and behaviour.
Cognitive Behavioural Therapy
One of the best-known psychological treatments associated with cognitive explanations is Cognitive Behavioural Therapy, usually called CBT.
As the name suggests, CBT combines cognitive and behavioural techniques. The cognitive side focuses on identifying and challenging unhelpful thoughts. The behavioural side focuses on changing behaviours that may maintain low mood.
A therapist may help a person identify automatic thoughts and examine the evidence for them.
For example:
“I failed one test, so I'm completely useless.”
The therapist might ask:
I. Have you actually failed everything?
II. What evidence supports this belief?
III. What evidence contradicts it?
IV. Could there be another explanation for the result?
V. What would you say to a friend in the same situation?
The aim is not simply to replace negative thoughts with unrealistic positive statements. Instead, the person learns to develop more balanced and evidence-based interpretations.
Behavioural techniques in CBT
CBT does not only involve talking about thoughts. Behaviour is also important.
Someone experiencing depression may gradually stop doing activities they previously enjoyed. They may avoid friends, stop exercising, spend more time in bed or lose interest in hobbies.
Unfortunately, withdrawing from activities can reduce opportunities for positive experiences. This can reinforce low mood.
A CBT approach may therefore involve gradually reintroducing meaningful and manageable activities.
For example, rather than expecting someone to completely change their lifestyle overnight, they might begin by: taking a short walk, completing one manageable task, speaking to a friend, returning to a hobby and establishing a regular routine.
Small behavioural changes can provide opportunities for positive experiences and a sense of achievement.
Evaluating the cognitive explanation
One major strength of cognitive explanations is that there is evidence linking patterns of negative thinking with depression.
Research has found associations between negative beliefs, pessimistic thinking and depressive symptoms. The success of CBT also provides some support for the idea that changing thoughts and behaviours can help reduce depression.
However, there is an important limitation. It can be difficult to determine cause and effect.
Does negative thinking cause depression? Or does depression cause people to think more negatively?
It may be that the relationship works in both directions. Someone who becomes depressed may begin interpreting their experiences more negatively, meaning that negative thinking could sometimes be a consequence rather than the original cause.
Is depression only about thinking?
The answer is No.
Depression is a complex condition, and the cognitive approach is only one way of understanding it.
Biological explanations focus on factors such as genetics, brain chemistry and neurotransmitters. Psychological explanations focus on thoughts, behaviour and learning. Social explanations consider factors such as relationships, life circumstances, isolation and stressful experiences.
These approaches do not necessarily have to be treated as competing explanations. Human behaviour is complex, and several factors can interact.
For example, biological vulnerability may make someone more susceptible to depression, while stressful experiences and negative thinking patterns may contribute to the onset or maintenance of symptoms.
This is why psychologists often consider multiple levels of explanation.
Why does CBT matter?
CBT is particularly interesting from a psychological perspective because it demonstrates how theory can be applied to treatment.
Beck and Ellis developed explanations focused on cognition.These ideas contributed to therapeutic approaches that encourage people to examine their thoughts and beliefs.
CBT therefore gives us an example of a broader principle in psychology: Research can influence theory, and theory can influence practical interventions.
However, no treatment works in exactly the same way for every person.
The appropriate form of support depends on the individual and the nature and severity of their difficulties.
Depression and everyday life
The cognitive approach can be particularly easy to understand when applied to everyday experiences. Imagine a student receives a lower grade than expected.
The event itself is disappointing. But there are several possible interpretations.
One might be:
“I need to improve my understanding of this topic.”
Another might be:
“I'm stupid.”
Another might be:
“There's no point studying because I'll fail anyway.”
Each interpretation could lead to different emotions and behaviours. The first may encourage problem-solving. The second could damage self-esteem. The third could lead to withdrawal and reduced motivation. This illustrates why psychologists are interested in the relationship between thoughts, emotions and behaviour.
Final thought
Depression is a complex area of psychology because it demonstrates how closely thoughts, emotions and behaviour can interact.
Beck's negative triad shows how a person can develop negative views of the self, world and future. Ellis's ABC model highlights the importance of the beliefs we hold about events. CBT then applies these principles by helping people identify unhelpful patterns of thinking while also encouraging constructive changes in behaviour.
However, these theories should not be interpreted as suggesting that depression is simply a matter of “thinking negatively” or that people can overcome it by choosing to be more positive. Depression is a serious and complex mental health condition, and different biological, psychological and social factors may contribute to an individual's experience.