What does Edexcel Psychology Topic 3 Psychological problems cover?

Topic 3 asks how psychological problems would affect you. It covers defining and measuring mental health and how attitudes have changed, unipolar depression and addiction, the incidence of mental health problems, the influence of genes (including Caspi et al. 2003), the cognitive theory of depression and the learning theory of addiction, and treatments including cognitive behavioural therapy and drugs. It is examined in Paper 1.

How is depression explained in Topic 3?

Two explanations are required. The genetic explanation uses Caspi et al. (2003), who found people with the short version of a serotonin-transporter gene were more likely to become depressed after stressful events, showing a gene-environment interaction. The cognitive theory (Beck) says depression is caused by faulty negative thinking, summarised in the negative triad: negative views of the self, the world and the future.

What treatments are covered for depression and addiction?

For depression, cognitive behavioural therapy challenges negative thinking and uses behavioural activities, while antidepressants (such as SSRIs) raise serotonin activity. For addiction, drug treatments include aversion therapy (pairing the substance with something unpleasant) and substitute drugs (such as nicotine replacement), while behavioural and cognitive approaches (including CBT) tackle the triggers and thinking. Treatments are often combined.

How should I revise Topic 3 Psychological problems?

Learn how mental health is defined and why recorded incidence has risen, then the genetic and cognitive explanations of depression (Caspi and Beck's negative triad) and the genetic and learning explanations of addiction (conditioning and Young). Secure how each treatment works and links to its explanation, and practise evaluate questions comparing CBT with drugs, which reward a balanced, justified conclusion.

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Edexcel GCSE Psychology Topic 3 Psychological problems: a complete overview of depression, addiction and treatments

Q: How is addiction explained in Topic 3?

Addiction is explained by genes (a vulnerability that runs in families) and by the learning theory. Classical conditioning links cues to the substance so they trigger cravings, and operant conditioning strengthens the behaviour through positive reinforcement (a pleasant reward) and negative reinforcement (relief from stress or withdrawal). Young (2007) showed addiction can apply to behaviours such as internet use, not only substances.

A deep-dive Edexcel GCSE Psychology guide to Topic 3, Psychological problems. Covers defining mental health, unipolar depression and addiction, the influence of genes (Caspi et al.), the cognitive and learning explanations, and treatments including CBT and drugs.

Generated by Claude Opus 4.816 min read1PS0 Topic 3Updated 2026-06-02

Reviewed by: AI editorial process; not yet individually human-reviewed

Jump to a section

What Topic 3 actually demands
Defining and measuring mental health
Explaining depression
Explaining addiction
Treatments
How Topic 3 is examined
Check your knowledge

What Topic 3 actually demands

Psychological problems asks the guiding question "how would psychological problems affect you?". It runs from defining and measuring mental health, through two disorders (unipolar depression and addiction) with their explanations, to their treatments. Edexcel tests precise knowledge of the explanations (genetic, cognitive and learning) and treatments, and the ability to evaluate and compare them.

This guide walks through the topic in specification order, then sets out the exam patterns. Each part has a matching dot-point page with practice questions; this overview ties them together.

Defining and measuring mental health

The topic starts with what mental health and mental health problems are, how attitudes have shifted from stigma towards a more medical, accepting view, and the incidence of problems. A key exam skill is distinguishing a rise in recorded cases (more diagnosis and awareness) from a rise in true incidence (real-world causes such as stress).

Explaining depression

Unipolar depression is explained two ways. The genetic explanation uses Caspi et al. (2003): the short version of a serotonin-transporter gene raised the risk of depression after stress, a gene-environment interaction. The cognitive theory (Beck) blames faulty negative thinking, summarised in the negative triad (negative views of self, world and future). Most cases involve both biology and thinking.

Explaining addiction

Addiction is explained by genes (a vulnerability that runs in families) and the learning theory. Classical conditioning links cues to the substance so they trigger cravings; operant conditioning strengthens the behaviour through positive reinforcement (reward) and negative reinforcement (relief from stress or withdrawal). Young (2007) extended addiction to behaviours such as internet use.

Treatments

Both disorders have biological and psychological treatments. For depression, CBT challenges negative thinking and adds behavioural activities, while antidepressants (SSRIs) raise serotonin activity. For addiction, aversion therapy and substitute drugs manage the physical side, while CBT tackles triggers and thinking. The key exam move is comparing treatments and concluding that they are often combined, with drugs giving fast relief and therapy giving lasting change.

How Topic 3 is examined

A typical Edexcel profile for Topic 3:

Multiple choice and short answer. Defining a mental health problem, or naming a part of the negative triad.
Describe questions. The cognitive theory of depression, or how aversion therapy works.
Explain questions. How Caspi supports a genetic role, or how operant conditioning leads to addiction.
Extended response. Evaluating drugs versus CBT, with a balanced, evidenced judgement and credit for written communication.

Check your knowledge

A mix of recall and applied questions covering Topic 3. Attempt them under timed conditions, then check against the solutions.

Describe the cognitive theory of depression. (3 marks)
Explain how Caspi et al. (2003) supports a role for genes in depression. (4 marks)
Describe how cognitive behavioural therapy is used to treat depression. (4 marks)
Explain how operant conditioning can lead to addiction. (4 marks)
Describe how aversion therapy is used to treat addiction. (4 marks)
Explain one reason recorded mental health problems may have increased. (2 marks)
Evaluate the use of antidepressants compared with CBT to treat depression. (6 marks)

Solutions

Q1: Depression is caused by faulty negative thinking. Beck's negative triad is negative views of the self, the world and the future, and cognitive biases (overgeneralising, focusing on the negative) maintain the low mood.
Q2: Caspi found people with the short version of a serotonin-transporter gene were more likely to become depressed after stressful events than those with the long version, supporting a genetic vulnerability that interacts with the environment.
Q3: The therapist helps the person identify negative automatic thoughts and the negative triad, challenge them by testing the evidence, and replace them with realistic ones, plus behavioural activities to break the low-mood cycle.
Q4: An addictive behaviour is positively reinforced by a pleasant reward (a high or win) and negatively reinforced by removing something unpleasant (stress or withdrawal), so the repeated reward strengthens it into a habit.
Q5: Based on classical conditioning, the substance is paired with something unpleasant (for example a drug causing nausea), so a negative association forms and the person is put off using it.
Q6: Reduced stigma and greater awareness mean more people recognise symptoms and seek help, so more cases are diagnosed and recorded, even if the true rate has not risen as much.
Q7: Antidepressants work quickly with little effort but have side effects and do not fix the thinking; CBT treats the cause and gives lasting skills but takes time and effort. Conclusion: they are often combined, with drugs giving fast relief and CBT lasting change.

Sources & how we know this

Pearson Edexcel GCSE (9-1) Psychology (1PS0) specification — Pearson Edexcel (2017)