Theories of depression and interventions or therapies for depression

What you'll learn

• How biological and psychological explanations try to explain depression.
• What serotonin, negative schemas and attributions mean.
• How antidepressant medication and CBT aim to improve mental health.
• What Wiles' study of the effectiveness of CBT found, and how to evaluate it.

Before we start: what is depression?

Depression is more than feeling sad for a day. In psychology, it is treated as a mental health problem involving a pattern of symptoms that can affect mood, thoughts, behaviour, sleep, appetite and everyday functioning.

For GCSE Psychology, you do not need to diagnose depression. You need to understand two explanations for it and two ways it can be treated.

Theories of depression

A theory is an explanation of why something happens. The spec focuses on two broad explanations of depression:

• a biological explanation, linked to nature
• a psychological explanation, linked to nurture

Nature and nurture

Nature means biological factors, such as genes, hormones, brain structures or brain chemicals. Nurture means factors from experience and environment, such as learning, relationships, life events and patterns of thinking.

Biological explanation: imbalance of neurotransmitters

The biological explanation says depression may be linked to an imbalance of neurotransmitters in the brain, especially serotonin.

Serotonin is involved in regulating mood, sleep and appetite. If serotonin activity is too low or not working normally, mood regulation may be disrupted. This could make a person more likely to experience symptoms of depression.

This is a nature explanation because it focuses on internal biological processes rather than learned thinking patterns or life experiences.

Evaluating the biological explanation

A strength is that it is scientific and can be linked to medical treatments. For example, some antidepressants increase serotonin activity, and many people’s symptoms improve when taking them. This supports the idea that brain chemistry is involved.

A weakness is that it can be reductionist. This means it may explain a complex mental health problem using just one factor, such as serotonin. Depression is often affected by many things, including stress, relationships, trauma, thinking style and social support.

Psychological explanation: negative schemas and attributions

The psychological explanation focuses on how a person interprets events. It suggests depression can be linked to negative schemas and negative attributions.

A person with depression may have negative schemas about:

• themselves: “I am a failure”
• the world: “Nobody can be trusted”
• the future: “Nothing will ever improve”

They may also make negative attributions. For example, after failing a test, they might think, “It is all my fault, I always fail, and I will fail at everything.” This type of attribution is:

• internal: blaming themselves
• stable: thinking it will always be this way
• global: thinking it affects everything

Evaluating the psychological explanation

A strength is that it explains why two people can experience the same event differently. One person may see a bad test result as disappointing but fixable, while another may see it as proof they are worthless.

Another strength is that it leads directly to cognitive behaviour therapy, which aims to change unhelpful thoughts and behaviours.

A weakness is that negative thinking may be a symptom of depression rather than the original cause. It can be difficult to know whether negative thoughts caused depression or whether depression caused negative thoughts.

Interventions or therapies for depression

An intervention or therapy is a treatment used to improve mental health. The spec focuses on:

• antidepressant medication
• cognitive behaviour therapy, usually shortened to CBT

Reductionist and holistic perspectives

A reductionist perspective breaks a complex issue down into one main factor. For example, treating depression mainly as a serotonin imbalance is reductionist.

A holistic perspective looks at the whole person, including biology, thoughts, behaviour, relationships and environment. Combining medication with CBT can be seen as more holistic because it targets both brain chemistry and thinking/behaviour patterns.

Antidepressant medications

A common type is an SSRI, which stands for selective serotonin reuptake inhibitor. Reuptake is when serotonin is reabsorbed by the nerve cell that released it. SSRIs reduce this reabsorption, so serotonin stays available for longer between nerve cells.

This may help improve mood, motivation and sleep over time.

Evaluating antidepressants

Antidepressants can be effective, especially for people with moderate or severe depression. They can also be useful when someone feels too low or exhausted to engage with talking therapy.

However, they may have side effects, they do not work for everyone, and symptoms can return after stopping. They also do not directly teach coping skills or challenge negative thinking.

Cognitive behaviour therapy (CBT)

CBT is based on the idea that thoughts, feelings and behaviours influence each other. If someone thinks “I am a failure”, they may feel hopeless and withdraw from others. That withdrawal can then make their mood worse, creating a vicious cycle.

CBT tries to break this cycle by helping the person identify negative automatic thoughts, test whether they are realistic, replace them with more balanced thoughts, and gradually re-engage in helpful activities.

Evaluating CBT

CBT can be effective because it teaches skills the person can keep using after therapy ends. It also avoids drug side effects and targets the negative schemas and attributions linked to the psychological explanation.

However, CBT requires effort, motivation and access to trained therapists. It may be difficult for someone with very severe depression to complete homework tasks or attend sessions regularly. It may also be less appropriate if the person’s main difficulties come from ongoing social problems, such as unsafe housing or abuse, unless those wider issues are also addressed.

Wiles' study of the effectiveness of CBT

Wiles' study of the effectiveness of CBT is the named study for this part of the spec.

Aim

The aim was to investigate whether CBT, added to usual care, was effective for people with depression who had not responded well to antidepressant medication.

Method

Wiles used a randomised controlled trial. Participants with depression were randomly allocated to one of two groups:

• usual care only, such as continuing antidepressant treatment through their GP
• usual care plus CBT, involving a course of CBT sessions

The study collected quantitative data about depression symptoms, including whether participants showed a clear improvement over time.

Results

A higher percentage of participants improved in the group receiving CBT plus usual care compared with usual care alone. For example, after six months, about 46% of the CBT plus usual care group responded to treatment, compared with about 22% of the usual care group.

Conclusion and link to theory

Wiles concluded that CBT can be an effective treatment for depression, especially when added to usual care for people who have not improved enough with antidepressants alone.

This supports the psychological explanation because changing thoughts and behaviours can reduce depressive symptoms. It also supports a more holistic approach because CBT was used alongside medication rather than replacing it completely.

Evaluation of Wiles' study

A strength is the use of a randomised controlled trial. Random allocation reduces participant differences between groups, making the comparison fairer.

Another strength is that the study used real patients receiving care through ordinary health services, so it has good real-world relevance.

A limitation is that participants knew whether they were receiving CBT, so expectations may have affected results. Also, the study tested CBT plus usual care, not CBT completely on its own.

Ethically, participants were a potentially vulnerable group, so researchers needed informed consent, confidentiality, the right to withdraw, protection from harm and appropriate support. The control group still received usual care, which helped reduce the ethical problem of withholding treatment.