How does the medical model explain and treat mental disorders, and how does it compare with psychological approaches?
Treatments and the medical model: the assumptions of the medical model, drug therapies, the role of biochemistry, and a comparison with psychological treatments and their effectiveness.
An Edexcel A-Level Psychology answer to treatments and the medical model, covering the assumptions of the medical model, drug therapies and biochemistry, comparison with psychological treatments such as CBT, GRAVE evaluation and how treatment effectiveness is measured.
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What this dot point is asking
Edexcel wants you to outline the medical model, describe drug therapies and their biochemical basis, compare them with psychological treatments, and evaluate how treatment effectiveness is judged. It pulls together the explanations and treatments for schizophrenia and depression into a single framework.
The answer
The medical model
Drug therapies and biochemistry
Drugs are convenient (a tablet rather than weekly therapy), act relatively quickly and need little effort from the patient, which makes them practical for severe or acute cases. But they treat symptoms rather than causes, carry side effects (tardive dyskinesia, sedation, weight gain) and some, such as benzodiazepines, risk tolerance and dependence.
Comparison with psychological treatments
Evaluating effectiveness
Effectiveness is judged through randomised controlled trials that compare a treatment with a placebo and with other treatments, through relapse rates over time, and through measures of everyday functioning. The double-blind procedure (neither patient nor clinician knows who gets the active treatment) controls for expectation and experimenter bias. A treatment that beats placebo on a significance test, with low relapse and improved functioning, is judged effective.
Evaluation (GRAVE)
- Generalisability. Drug trials often exclude patients with comorbid disorders or use selected samples, so the high success rates may not generalise to the messier real-world clinical population.
- Reliability. Standardised dosing, manualised therapy and validated symptom scales make trials replicable, so effectiveness findings are reliable.
- Application. The medical model has freed many patients from institutions and allows community living; its drugs are cheap to deliver at scale, a major public-health benefit.
- Validity. A large placebo response and the medical model's reductionism (reducing disorder to biochemistry) cast doubt on whether drugs work for the reasons claimed and whether they address the true cause.
- Ethics. Drug side effects, dependence and consent issues (patients lacking insight) must be weighed; the non-blaming stance of the medical model is an ethical strength.
Examples in context
Example 1. Antipsychotics and the move to community care. Before chlorpromazine was introduced in the 1950s, people with severe schizophrenia were often confined long-term in psychiatric institutions. Antipsychotic drugs, by reducing positive symptoms, made it possible for many patients to live in the community with outpatient support, a process called deinstitutionalisation. This is a strong real-world application of the medical model. The evaluation point is that drugs alone are not enough: without psychological and social support, some patients relapse or are lost to care, which is why current best practice combines medication with CBT, family therapy and community services.
Example 2. The placebo effect in antidepressant trials. Meta-analyses of antidepressant trials (for example Kirsch's work) found that a large share of the improvement seen on antidepressants is matched by improvement on placebo, especially in mild to moderate depression. This does not mean the drugs do nothing, but it shows that expectation and the therapeutic relationship contribute substantially to outcomes. It is a key evaluation point: it challenges a purely biochemical reading of why drugs work and supports the use of placebo-controlled, double-blind trials to measure the genuine pharmacological effect.
Try this
Q1. Outline the assumptions of the medical model of mental disorder. [3 marks]
- Cue. Disorders are illnesses with biological causes (biochemistry, genetics or brain structure), are diagnosed from symptoms using classification systems, and are treated medically, mainly with drugs.
Q2. Compare one advantage of drug therapy with one advantage of CBT. [4 marks]
- Cue. Drugs act quickly and need little effort from the patient, useful in acute crises; CBT addresses the underlying thoughts and gives lasting coping skills without physical side effects.
Q3. Assess how the effectiveness of treatments for mental disorders is measured. [8 marks]
- Cue. Discuss randomised controlled trials, placebo and double-blind controls, significance testing, relapse rates and functioning; evaluate problems such as the placebo response, publication bias and the difficulty of blinding psychological therapies.
Exam-style practice questions
Practice questions written in the style of Pearson Edexcel exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Edexcel 20188 marksCompare the medical model with psychological approaches to treating mental disorders. [8 marks]Show worked answer →
A compare question needs points of similarity and difference, balanced across the two approaches (AO1 plus AO3).
The medical model treats disorders as illnesses with biological causes (biochemistry, genes, brain structure) and uses drugs (antipsychotics blocking dopamine, SSRIs raising serotonin, benzodiazepines enhancing GABA). Psychological approaches treat disorders as products of thoughts, learning or relationships and use therapies (CBT, systematic desensitisation, token economies).
Comparison points: drugs act fast and need little patient effort, useful in acute crises, but treat symptoms not causes and carry side effects and dependence; psychological treatments address causes and give lasting skills with no physical side effects but take longer and need effort. The medical model is reductionist and deterministic; psychological approaches are more holistic. Both are evidence-based; combined treatment is often most effective.
Markers reward genuine comparison (not two separate descriptions), named drugs and therapies, and a judgement (complementary, often combined).
Edexcel 20216 marksIn a drug trial, of patients on an antidepressant improved, compared with of on a placebo. Calculate the improvement rate (as a percentage) for each group and explain what the comparison tells you about the drug's effectiveness. [6 marks]Show worked answer →
A quantitative item: show the calculation (AO2) then interpret (AO3).
Drug group improvement rate: . Placebo group improvement rate: .
Interpretation: a placebo controls for the expectation of getting better, so the placebo improvement () shows how much improvement happens without an active drug. The drug group improved more (), a difference of percentage points, which suggests the drug has a real effect beyond expectation.
However, the substantial placebo response () warns that much improvement is not due to the drug's biochemistry. To be confident the difference is real and not chance, an inferential test (chi-square on these frequency counts) is needed, and the size and durability of the effect (relapse rates) should be checked.
Markers reward both correct percentages, the role of the placebo as a control for expectation, and the point that the difference suggests a real drug effect but needs a significance test.
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Sources & how we know this
- Pearson Edexcel A-Level Psychology (9PS0) specification — Pearson Edexcel (2015)