PS20: Depression
Understanding depression: symptoms, biological explanations (genetics, neurotransmitters), psychological explanations (cognitive, behavioural), and treatments including CBT and medication.
Depression
Understanding depression: symptoms, biological explanations (genetics, neurotransmitters), psychological explanations (cognitive, behavioural), and treatments including CBT and medication.
Key Fact: Depression symptoms: persistent low mood, loss of interest/pleasure (anhedonia), changes in sleep and appetite, fatigue, difficulty concentrating, feelings of worthlessness, and suicidal thoughts. Diagnosis requires symptoms lasting at least 2 weeks.
Key Fact: Biological explanations: genetics (twin studies show 37% concordance in MZ vs 15% in DZ twins - McGuffin et al.); neurotransmitter imbalance (low serotonin and noradrenaline); the diathesis-stress model: genetic predisposition + life events trigger depression.
Key Fact: Cognitive explanations: Beck's negative triad - negative views about the self, the world, and the future create a cycle of depression. Seligman's learned helplessness: repeated failure leads to belief that outcomes are uncontrollable, causing depression.
Key Fact: Biological treatment: SSRIs (e.g. Prozac) increase serotonin by preventing reuptake at synapses. Effective for many but: side effects (nausea, insomnia, loss of libido), 30-40% of patients don't respond, treats symptoms not causes, withdrawal effects.
Key Fact: Psychological treatment: CBT (Cognitive Behavioural Therapy) identifies and challenges negative automatic thoughts and beliefs, replacing them with realistic ones. Beck's CBT: test negative beliefs against evidence, develop alternative interpretations. Effective: March et al. found CBT + SSRI most effective for adolescents. But: requires motivation, takes time, not available for all.
📋 Key Vocabulary and Concepts
For Depression, you must know:
- Depression
- Anhedonia
- Concordance rate
- SSRI
- Serotonin
- Noradrenaline
- Beck's negative triad
- Cognitive Behavioural Therapy (CBT)
- Learned helplessness
- Diathesis-stress model
- Negative automatic thoughts
- Cognitive restructuring
- Twin study
- Electroconvulsive therapy (ECT)
❓ Practice Questions
Q1: Describe biological and cognitive explanations of depression and evaluate each one.
Q2: Compare SSRI medication with CBT as treatments for depression.
Q3: Evaluate whether depression is best explained as a biological or a psychological condition.
✅ Answers
- Biological: genetics (twin studies show heritability), low serotonin/noradrenaline (supported by SSRI effectiveness). Cognitive: Beck's negative triad (negative self, world, future views maintain depression), Seligman's learned helplessness (uncontrollable outcomes lead to hopelessness). Biological is supported by drug effectiveness but is reductionist; cognitive explains thinking patterns but may not address biological vulnerability.
- SSRIs: increase serotonin, effective for 60-70% of patients, quick to prescribe, but side effects and treat symptoms not causes. CBT: challenges negative thoughts, teaches skills for long-term management, no side effects, but requires effort and time, therapist availability is limited. March et al. found CBT + SSRI combined was most effective for adolescent depression (71% improvement vs 61% SSRI alone vs 43% CBT alone).
- Depression is best explained by an interaction of both: genetic vulnerability (biological) may be triggered by life events (social), which then activate negative thinking patterns (cognitive). The diathesis-stress model integrates biological predisposition with environmental triggers. Neither explanation alone fully accounts for depression - a biopsychosocial approach is most comprehensive.
🎯 Exam Tips
- Beck's negative triad: Negative SELF + Negative WORLD + Negative FUTURE = depression.
- SSRIs = increase serotonin (biological). CBT = change negative thoughts (cognitive). Best = BOTH combined.
- Diathesis-stress model: GENETIC vulnerability + LIFE EVENTS = depression. Nature + nurture.
📝 Exam Technique
Psychology Exam Tips:
When evaluating depression explanations and treatments, always consider: is the explanation reductionist? Does the treatment address causes or symptoms? Is the evidence causal or correlational? Use the biopsychosocial approach for comprehensive evaluation.
When evaluating depression explanations and treatments, always consider: is the explanation reductionist? Does the treatment address causes or symptoms? Is the evidence causal or correlational? Use the biopsychosocial approach for comprehensive evaluation.
⚠️ Common Errors
Watch Out!
Students often make mistakes here. Wrong: Depression is caused by a chemical imbalance, so the only effective treatment is medication. Correct: While low serotonin is associated with depression, this correlation doesn't prove it's the cause. SSRIs increase serotonin immediately but take weeks to improve mood, suggesting the relationship is more complex. CBT is as effective as medication for mild-moderate depression and more effective at preventing relapse (Hollon et al.). Combined treatment is most effective. Depression has multiple causes, so multiple treatment approaches are needed.
✍️ Model Answer
Full-Mark Response
Evaluate the relative effectiveness of biological and psychological treatments for depression.
A grade 9 response will: describe SSRIs (mechanism, effectiveness, limitations); describe CBT (mechanism, effectiveness, limitations); compare using research evidence (March et al.: combined is best); evaluate biological treatment (effective but side effects, treats symptoms); evaluate psychological treatment (addresses thinking but requires motivation, limited availability); conclude: for moderate-severe depression, combined treatment (SSRI + CBT) is most effective. For mild depression, CBT alone may be sufficient. Treatment should be personalised - the biopsychosocial model suggests different patients may benefit from different combinations.
📊 AO Deep Dive
Assessment Objective Focus: Depression
AO1 — Knowledge: Demonstrate knowledge of Depression including key definitions, research studies and psychological terminology.
AO2 — Application: Apply your understanding of Depression to real-world scenarios and given contexts. Use research evidence to support your points.
AO3 — Analysis & Evaluation: Evaluate psychological theories and studies related to Depression, considering methodological strengths and weaknesses, and reaching a balanced conclusion.
📝 Exam Questions by Topic
🎬 Video Resources
Detailed Notes
Key Studies and Theories in Depression
Depression is a core topic in GCSE Psychology that requires understanding of key studies, theories and research methods. The AQA, OCR and Edexcel specifications all require you to know specific studies in detail, evaluate their methodology, and apply psychological concepts to real-life scenarios. When studying depression, focus on: the aims, methods, results and conclusions of key studies; the strengths and weaknesses of the research methods used; and how psychological understanding of depression applies to everyday life.
Key studies in this area typically use specific research methods such as experiments, observations, self-report (questionnaires and interviews), or correlational analysis. When evaluating studies, consider: reliability (can the study be replicated?); validity (does it measure what it claims to measure?); ethics (were participants protected from harm?); generalisability (can the findings be applied beyond the study sample?); and usefulness (does the research have practical applications?).
GCSE Psychology emphasises the application of psychological knowledge to real contexts. You must be able to explain how understanding of depression can be used to improve people’s lives, influence policy, or solve practical problems.
GCSE Example: Key Studies and Theories in Depression
When writing about a study related to depression, use the AMRC format: Aim (what was the study trying to find out?), Method (how was it conducted — design, sample, procedure?), Results (what were the key findings?), Conclusions (what do the results mean?).
Evaluating Research in Depression
Evaluation is a crucial skill in GCSE Psychology. When evaluating studies related to depression, use the GRAVE method: Generalisability (can the findings be applied to the wider population?), Reliability (are the results consistent if the study is repeated?), Applications (how can the findings be used in real life?), Validity (does the study measure what it claims to measure?), and Ethics (were participants treated ethically?).
Research methods commonly used in depression research include: laboratory experiments (high control but low ecological validity), field experiments (more realistic but less control), natural experiments (no manipulation of variables), case studies (in-depth but not generalisable), questionnaires (large samples but social desirability bias), and observations (natural behaviour but ethical concerns). Each method has strengths and limitations that must be evaluated in context.
Ethical issues in depression research include: informed consent (participants must agree to take part), debriefing (explaining the true purpose after the study), confidentiality (protecting participants’ identities), protection from harm (no physical or psychological damage), and right to withdraw (participants can leave at any time). The BPS Code of Conduct governs ethical standards in UK psychological research.
GCSE Example: Evaluating Research in Depression
When evaluating Milgram’s obedience study, you might note: low generalisability (all male, American sample); high reliability (standardised procedure with 65% obedience rate); useful applications (understanding wartime atrocities); low ecological validity (artificial laboratory setting); and serious ethical concerns (deception, psychological distress).
Applying Depression to Real Life
GCSE Psychology requires you to apply psychological understanding of depression to everyday situations. Consider how the theories and studies you have learned about explain real behaviour: How does depression affect people in schools, workplaces, families and communities? What interventions or strategies could improve outcomes based on psychological evidence?
When applying depression to real-life scenarios, use the following structure: identify the relevant psychological concept, explain how it applies to the scenario, support your explanation with evidence from a named study, and evaluate the strength of the application (are there limitations or alternative explanations?).
The most effective GCSE Psychology answers show a clear link between theory, evidence and application. Avoid vague statements like ‘psychology can help’ — instead, specify which psychological concept applies, which study supports it, and exactly how it could be used in the given scenario.
GCSE Example: Applying Depression to Real Life
A strong application answer: ‘Understanding of depression could help in schools by [specific application]. This is supported by [named study] which found that [specific finding]. This means that [specific practical recommendation]. However, a limitation is [specific weakness of applying this research].’
Comparison Table
| Evaluation Criterion | What It Means | How to Assess It |
|---|---|---|
| Generalisability | Can findings apply beyond the sample? | Consider sample size, representativeness, culture |
| Reliability | Are results consistent if repeated? | Standardised procedures, replicability |
| Validity | Does it measure what it claims? | Ecological validity, construct validity |
| Ethics | Were participants protected? | Consent, debriefing, protection from harm |
| Applications | Is the research useful? | Practical implications, real-world relevance |
Additional Practice Questions
Q: Describe one study related to depression and evaluate its methodology using the GRAVE method.
A: A key study in depression investigated [aim] using [method] with [sample]. The results showed [key finding], leading to the conclusion that [interpretation]. Evaluation: Generalisability — limited by [sample issue]; Reliability — strengthened by [standardisation]; Applications — useful for [practical application]; Validity — limited by [validity concern]; Ethics — problematic because [ethical issue]. Overall, the study makes a valuable contribution but has limitations that should be considered when applying the findings.
Q: Explain how psychological understanding of depression could be applied to improve a real-life situation.
A: Understanding of depression can be applied to improve [specific situation]. Research by [named psychologist] found that [key finding], which suggests that [practical recommendation]. For example, in a school context, this understanding could lead to [specific intervention] which would benefit people by [specific improvement]. However, individual differences mean that not everyone will respond the same way, so a personalised approach may be needed.
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