HookEight sane people who could not get out
In 1973 eight perfectly healthy people — among them a psychology graduate, a paediatrician and a painter — walked into twelve American psychiatric hospitals and each said the same thing: they could hear a voice saying 'empty', 'hollow', 'thud'. Beyond that single lie they behaved entirely normally. Every one was admitted; all but one were diagnosed with schizophrenia; and they were kept in for an average of nineteen days — one for fifty-two — before being discharged, not as cured but as 'schizophrenia in remission'. Staff never spotted the deception, though real patients often did. David Rosenhan called his study 'On being sane in insane places', and it detonated one uncomfortable question: if trained professionals cannot reliably tell the disordered from the well, how sound is the diagnosis itself?
That question — the reliability and validity of diagnosis — is where this topic starts and the pressure it puts on every explanation and treatment that follows. Schizophrenia is a psychotic disorder affecting roughly one person in a hundred, in which thought, emotion and contact with reality fracture. AQA asks you to classify it, explain it both biologically and psychologically, treat it with drugs and with talking therapies, and finally hold both halves together in the interactionist diathesis-stress model. Keep Rosenhan in mind throughout: the science here is real, but so are its blurred edges.
ModelClassification and the problem of diagnosis
Schizophrenia is diagnosed against classification systems — the ICD in Europe and the DSM in the US — by identifying clusters of symptoms. Positive symptoms are additions to normal experience: hallucinations (usually auditory, hearing voices) and delusions (fixed false beliefs, such as being persecuted or having grandiose powers). Negative symptoms are losses of normal function: avolition (a collapse of motivation and goal-directed activity) and speech poverty or alogia (reduced quantity and quality of speech).
The reliability and validity of that process is the topic's spine. Diagnosis should be reliable — two clinicians reaching the same verdict — and valid — actually identifying a real, distinct disorder. Four threats recur. Co-morbidity: schizophrenia so often co-occurs with depression or substance abuse that it may not be a single condition. Symptom overlap: positive and negative symptoms are shared with bipolar disorder, blurring the boundary. Culture bias: hearing voices is read as psychotic in Britain but as a spiritual experience elsewhere, and African-Caribbean men in the UK are diagnosed far more often, hinting at clinician bias. Gender bias: women are sometimes under-diagnosed because they function better socially.
Rosenhan is the case that ties these together: sticky diagnostic labels and the failure to detect sane behaviour expose exactly how shaky reliability and validity can be.
MechanismBiological explanations: genes and dopamine
The biological account says schizophrenia is a brain disorder with a strong inherited component. Family studies by Gottesman show risk rising steeply with genetic closeness: about 1% in the general population, roughly 9% in siblings, and around 48% in identical (MZ) twins against 17% in non-identical (DZ) twins. Because MZ concordance is well below 100%, genes cannot be the whole story — but they clearly load the dice. Schizophrenia is polygenic: Ripke's large-scale study implicated over 100 genetic loci, so there is no single 'schizophrenia gene'. Neural correlates such as enlarged ventricles (fluid-filled brain spaces) are also associated with the disorder.
The most examined biological idea is the dopamine hypothesis. The original version blamed an excess of the neurotransmitter dopamine, or too many/too sensitive D2 receptors. The revised version is more precise and more defensible: hyperdopaminergia in subcortical areas (the mesolimbic pathway) drives positive symptoms like hallucinations, while hypodopaminergia — too little dopamine — in the prefrontal cortex drives negative and cognitive symptoms.
The dopamine hypothesis is best evaluated with converging drug evidence, and this is the paragraph examiners love. Point: the hypothesis is strongly supported by how different drugs alter dopamine. Evidence: amphetamines, which increase dopamine activity, can induce hallucinations and delusions indistinguishable from schizophrenia in healthy people, and L-dopa, given to raise dopamine in Parkinson's patients, can trigger similar psychotic episodes; conversely, antipsychotic drugs that block D2 receptors reduce positive symptoms. Explain: because manipulating dopamine up produces symptoms and manipulating it down relieves them, dopamine looks causal rather than merely correlated — a rare thing in psychology. Counterpoint — the mark-winner: yet newer atypical antipsychotics like clozapine also act heavily on serotonin and still work, and some patients respond poorly to any dopamine drug, so dopamine is necessary but plainly not sufficient. That final concession is what lifts the answer from description into evaluation.
MechanismPsychological explanations: family and cognition
Psychological explanations look to experience and thought rather than biology. Family dysfunction theories argue disordered relationships raise risk. The schizophrenogenic mother (Fromm-Reichmann) was a cold, controlling, rejecting parent said to create a paranoid climate. The double-bind theory (Bateson) proposed that a child repeatedly trapped in contradictory messages — where doing the right thing is also somehow wrong — learns that the world is confusing and dangerous, fostering disorganised thinking. Most robustly, research on expressed emotion (EE) shows that patients returning to families high in criticism, hostility and emotional over-involvement relapse far more often — though EE is best seen as a cause of relapse rather than of the disorder itself.
Cognitive explanations focus on faulty information processing. Frith argued schizophrenia involves dysfunction in metarepresentation — the ability to reflect on our own thoughts and behaviour — which, if impaired, would make inner speech feel like an external voice, explaining hallucinations. A deficit in central control — the ability to suppress automatic responses — could explain disorganised speech, as one thought derails into the next.
The evaluative balance: family and cognitive accounts explain symptoms biology struggles with, and the therapies built on them work — but they describe processes that maintain schizophrenia better than they prove what first causes it, and older family theories unfairly blamed parents.
MechanismDrug therapy: typical and atypical antipsychotics
Antipsychotic drugs are the front-line biological treatment, and they fall into two generations. Typical antipsychotics, such as chlorpromazine, arrived in the 1950s and work as dopamine antagonists: they bind to and block D2 receptors, dampening dopamine transmission and so reducing positive symptoms like hallucinations and delusions. Chlorpromazine is also a sedative, which is why it was used to calm distressed patients. The drawback is that blocking dopamine broadly produces movement side effects — including tardive dyskinesia, involuntary facial movements that can be permanent.
Atypical antipsychotics, developed from the 1970s, aim to treat the disorder with fewer side effects and to help with negative symptoms too. Clozapine acts on dopamine but also on serotonin and glutamate receptors, improving mood and cognition; because it can dangerously lower white blood cell count, patients need regular blood tests. Risperidone was designed to bind more strongly to dopamine receptors at lower doses, reducing side effects further.
The evidence base is genuinely strong — trials and meta-analyses show antipsychotics reduce symptoms and relapse compared with placebo — which is a serious point for the biological approach. But drugs manage symptoms rather than curing the disorder; relapse is common on discontinuation; side effects harm adherence; and success arguably owes something to the calming effect rather than to correcting a specific chemical fault.
MechanismPsychological therapies and management
Three psychological approaches are on the specification, and it helps to be clear what each is actually for. Cognitive behaviour therapy (CBTp) does not remove symptoms but changes the patient's relationship to them: over roughly 12-20 sessions the therapist helps the person test the evidence for a delusion, and normalises experiences (many people hear voices) to reduce the distress and the sense of threat. It is recommended by NICE and improves functioning, though it works best alongside medication.
Family therapy targets the family system rather than the individual, aiming to reduce expressed emotion. By improving communication, lowering criticism and teaching relatives about the disorder, it cuts relapse rates — Pharoah's meta-analysis found clear reductions in readmission. It treats the family as an ally, reversing the blame of the old schizophrenogenic-mother theories.
Token economies apply operant conditioning to manage behaviour in institutional settings. Patients earn tokens — secondary reinforcers — for target behaviours like self-care or engagement, later exchanged for privileges. They do not treat the illness; they improve day-to-day functioning and quality of life on wards. The ethical criticism is sharp: withholding tokens can mean withholding comforts from very unwell people, and gains often fade outside the institution where the reinforcement stops.
ModelThe interactionist diathesis-stress model
The interactionist approach refuses the biology-versus-psychology dichotomy and says schizophrenia emerges from their interaction. The diathesis-stress model proposes that an individual carries a vulnerability (the diathesis) which only develops into the disorder when combined with a stressor. Meehl's original version made the diathesis a single 'schizogene', but the modern model is broader: the diathesis may be genetic OR an early trauma that alters the developing brain, and the stress may be biological (such as cannabis use in adolescence) OR psychological (such as a dysfunctional, high-EE family).
The evidence is compelling. Tienari's Finnish adoption study followed adoptees whose biological mothers had schizophrenia: those raised in psychologically healthy adoptive families rarely developed it, whereas those with the genetic vulnerability AND a critical, conflict-ridden adoptive home showed markedly elevated rates. Genes alone did not decide the outcome; neither did the environment. It took both.
Crucially, the model has a treatment implication the exam rewards: if the disorder is interactionist, the best therapy is too. Combining antipsychotics (targeting the biological diathesis) with CBT and family therapy (managing the stress) consistently outperforms either alone — which is exactly how schizophrenia is treated in practice.
A model 16-mark essay closes by using the interactionist model to adjudicate, and here is that final AO3 move annotated. Point: 'The interactionist model is arguably the most complete explanation because it accounts for evidence that defeats the single-factor accounts.' Evidence: 'Tienari et al. found adoptees with a genetic risk developed schizophrenia far more often only when raised in high-criticism families, while genetically at-risk children in healthy homes usually did not.' Explain: 'This directly explains why MZ twin concordance is only around 48% rather than 100% — the shared genes are a diathesis that requires environmental stress to be expressed, something the pure genetic model cannot accommodate.' Conclusion with reach: 'It also has practical value, since combining antipsychotics with family therapy outperforms either alone, showing the model earns its keep in the clinic as well as the lab.' Notice how the concordance figure from the biological section is recycled as evaluation here — a top-band answer makes its own earlier content do double duty.
VocabularyKey terms the mark scheme pays for
TrapsMisconceptions that cost marks
ExamWhat examiners want
AQA marks against AO1 (knowledge), AO2 (application to a stem) and AO3 (evaluation); a 16-mark essay is 6 AO1 and 10 AO3, so weight your writing toward evaluation. Where a question gives a named patient or scenario, weave their specific symptoms or family situation into the answer — describing the theory in the abstract when a stem is provided caps your AO2.
The reliability and validity of diagnosis is the topic's recurring AO3 currency: co-morbidity, symptom overlap, culture bias and gender bias can be deployed as evaluation of almost any explanation or treatment, and Rosenhan anchors them all. On the dopamine hypothesis, build the strongest paragraph from converging drug evidence (amphetamines and L-dopa induce symptoms; antipsychotics reduce them) and then concede the serotonin action of clozapine — causation, then its limit.
Quote figures where you can (1% base rate, ~48% MZ concordance) and name your evidence (Gottesman, Ripke, Tienari, Pharoah), because a citation earns full credit where 'studies show' earns partial. Finish essays with the interactionist diathesis-stress model as your adjudicating conclusion: use it to explain why single-factor accounts fail (MZ concordance is not 100%) and why combined drug-plus-therapy treatment works best. That synthesis is what the top band means by discussion that is thorough and effective.