The medical model of mental illness treats mental disorders in the same way as a broken arm, i.e., there is thought to be a physical cause.
This model has been adopted by psychiatrists rather than psychologists.
Supporters of the medical model see symptoms as outward signs of an inner physical disorder. If symptoms are grouped together and classified into a “syndrome,” they believe the true cause can eventually be discovered and appropriate physical treatment given.
Key Takeaways
- Definition: The medical model treats abnormal behaviour as an illness with an underlying physical cause, diagnosed through symptoms and treated with drugs, ECT, or surgery.
- Diagnostic Reliability: Rosenhan’s (1973) pseudopatient study found psychiatrists could not reliably tell the sane from the insane, though its findings have since been challenged.
- Labelling Critique: Szasz argued most “mental illness” is really problems in living, not brain disease, and that diagnosis can remove responsibility while increasing stigma.
- Treatment Trade-offs: Drugs, ECT, and psychosurgery can relieve symptoms but carry side effects, relapse risk, and ethical concerns around consent.
- Modern Evidence: A 2020 meta-analysis of 317 findings suggests most psychopathology fits a dimensional spectrum better than Kraepelin’s discrete disease categories.
- Successor Model: The biopsychosocial model, combining biological, psychological, and social factors, is now the field’s dominant alternative to a purely medical account.
Assumptions
The biological approach to psychopathology believes that disorders have an organic or
physical cause. The focus of this approach is on genetics, neurotransmitters, neurophysiology, neuroanatomy, etc.
The approach argues that mental disorders are related to the physical structure and functioning of the brain.
Behaviors such as hallucinations are “symptoms” of mental illness, as are suicidal ideas or extreme fears such as phobias about snakes and so on.
Different illnesses can be identified as “syndromes,” clusters of symptoms that go together and are caused by the illness.
These symptoms lead the psychiatrist to make a “diagnosis,” for example, “this patient is suffering from a severe psychosis; he is suffering from the medical condition we call schizophrenia.”
How a Diagnosis Is Reached
The psychiatrist makes a judgment of the patient’s behaviour, usually in a clinical interview after a relative or general practitioner has asked for an assessment.
In physical medicine, doctors weigh objective signs, such as blood test or X-ray results, more heavily than the patient’s own reported symptoms. Psychiatry has no equivalent biological test for most conditions. The psychiatrist relies far more on what the patient, and people close to them, describe.
The doctor judges whether the “patient” is behaving abnormally. This comes from asking questions and observing them directly. Judgment is also shaped by what relatives and others nearby say, and by context.
Is mental illness more likely to be diagnosed inside a mental hospital?
Diagnostic Criteria
In psychiatry, the psychiatrist must be able to validly and reliably diagnose different mental illnesses. Emil Kraepelin made the first systematic attempt to do this, publishing the first recognized textbook on psychiatry in 1883.
His claim was simple. Certain symptoms, he argued, occur together often enough to count as a disease. He treated each mental illness as a distinct type, describing its own origins, symptoms, course, and outcomes.
Kraepelin’s work is the basis of modern classification systems. The two most important are:
The Diagnostic and Statistical Manual of Mental Disorders (DSM)
This is the classification system used by the American Psychiatric Association. The first version (DSM 1) was published in 1952. The latest version is DSM V, published in 2013.
The International Classification of Diseases (ICD)
This is published by The World Health Organisation. Mental disorders were included for the first time in 1948 (ICD 6). The current version is ICD 10, published in 1992.
In order to diagnose someone, you would usually need some/all of the following:
- Clinical interview
- Careful observation of behavior, mood states, etc.
- Medical records
- Psychometric tests
On the basis of the diagnosis, the psychiatrist will prescribe treatment such as drugs, psychosurgery, or electroconvulsive therapy.
However, since the 1970s, psychiatrists have predominantly treated mental illnesses using drugs.
Critical Evaluation
The traditional categorical diagnostic systems used in mental health, like the DSM and ICD, were developed primarily for clinical utility to categorize mental disorders.
However, researchers have identified a number of limitations of these categorical systems for research purposes (Cuthbert & Kozak, 2013; Kotov et al., 2017):
- Heterogeneity within diagnoses – People with the same diagnosis may exhibit very different symptom profiles, so two people with “major depression” could share few common symptoms (Fried & Nesse, 2015). This makes it hard to draw generalizable conclusions about the disorder.
- Comorbidity and symptom overlap – Many symptoms, like insomnia or irritability, occur across numerous diagnoses. This makes teasing apart distinct disorders difficult when they share common symptom dimensions (Kotov et al., 2017)., 2020).
- Arbitrary diagnostic thresholds – There’s little evidence that mental disorders naturally fall into discrete categories versus lying along a continuum. However arbitrary thresholds are set for when a diagnosis applies (Haslam et al., 2020). This doesn’t fit a dimensional model of psychopathology.
- Low reliability and validity – Diagnoses based on categorical systems can have poor inter-rater reliability, test-retest reliability, and validity in terms of linking to biological correlates or treatment response (Regier et al., 2013). Rosenhan’s (1973) pseudopatient study, described in full below, is the clearest empirical test of this problem.
- Poor fit for tracking individual symptoms – Diagnostic categories are static and don’t capture dynamic changes in individual symptoms over time (Fisher et al., 2018).
- Questionable biological basis – The underlying biological and genetic basis for current diagnostic categories remains unclear (Cuthbert & Kozak, 2013).
Rosenhan (1973): Can Psychiatrists Tell the Sane from the Insane?
Aim: Rosenhan (1973) tested whether psychiatrists could reliably tell the difference between people who were genuinely mentally ill and those who were not.
Method: Eight psychiatrically normal “pseudopatients” presented at 12 different US psychiatric hospitals, each reporting one fabricated symptom: hearing a voice say “empty,” “hollow,” and “thud.” Once admitted, they stopped simulating any symptom and behaved normally.
A second study tested the opposite error. A hospital doubted the first result. Staff were told pseudopatients would try to gain admission over the next three months, and rated 193 genuine patients on how likely each was to be a pseudopatient. Rosenhan sent none at all.
Results: Every pseudopatient was admitted. Eleven of the twelve were diagnosed with schizophrenia, and none was detected as a fake. Stays ranged from 7 to 52 days, averaging 19.
Each was discharged not as “sane” but as “schizophrenia in remission.”
In the second study, 41 of the 193 genuine patients (21%) were judged by staff to be a likely pseudopatient. None had actually been sent.
Conclusion: Rosenhan concluded that psychiatric diagnosis said more about the context than about the patient. Robert Spitzer (1975) disagreed. He argued that reporting hallucinations is a genuine symptom, so admitting the pseudopatients reflected a reasonable response to deception, not unreliable diagnosis.
Journalist Susannah Cahalan (2019) later found Rosenhan’s own hospital records described far more severe symptoms than the single word reported in his paper. The study is historically influential but evidentially fragile.
This has led to calls for approaches focused more on dimensions, mechanisms, or neurobiological correlates rather than discrete categories (Insel et al., 2010).
Approaches like the Hierarchical Taxonomy of Psychopathology (HiTOP), network models, and the NIMH Research Domain Criteria (RDoC) aim to move beyond categorical diagnoses to study more fine-grained elements of mental health and illness.
Contemporary Research: Are Diagnostic Categories the Right Unit?
Aim: Haslam et al. (2020) set out to synthesise decades of taxometric research. These are statistical studies testing whether a form of psychopathology is better represented as a discrete category or a continuous dimension.
Method: The scope was huge. Researchers pooled 317 individual findings from 183 published articles. Each compared how well observed clinical data fit a dimensional versus a categorical structure, across a wide range of psychological constructs.
Results: Dimensional findings outnumbered categorical ones. The ratio was roughly five to one across the pooled literature.
Conclusion: Most psychopathology fits a continuum better than a discrete category with a clear cut-off. This undercuts the disease-entity assumption built into Kraepelin’s original classification and the categorical structure of the DSM and ICD.
Schizophrenia
The main biological explanations of schizophrenia are as follows:
- Genetics – there is considerable evidence of a genetic predisposition to develop schizophrenia.
- Biochemistry – the dopamine hypothesis argues that elevated levels of dopamine are related to symptoms of schizophrenia.
- Neuroanatomy – differences in brain structure (abnormalities in the frontal and
the pre-frontal cortex and enlarged ventricles) have been identified in people with schizophrenia.
Depression
The main biological explanations of depression are as follows:
- Genetic – there is considerable evidence that the predisposition to develop
depression is inherited. - Biochemistry, e.g., Amine hypothesis – low levels of monoamines, predominantly noradrenaline and serotonin.
- Neuroanatomy – damage to amine pathways in post-stroke patients.
- Neuroendocrine (hormonal) factors – the importance of stress hormones (e.g., cortisol) and overactivity of the HPA axis, which is responsible for the stress response.
OCD
The main biological explanations of OCD are as follows:
- Genetic – there is some evidence of a tendency to inherit OCD, with a gene
(Sapap3) recently identified. - Biochemistry – serotonin deficiency has been implicated.
- Neuroanatomy – dysfunctions of the orbital frontal cortex ( OFC ) over-activity in
basal ganglia and caudate-nucleus thalamus have been proposed. - Evolutionary – adaptive advantages of hoarding, grooming, etc.
Drug Treatment
The film one flew over the cuckoo’s nest demonstrates the way in which drugs are handed out like smarties merely to keep the patients subdued.
Note also in the film that the same type of drug is given to every patient, with no regard for their case history or symptoms. The aim is merely to drug them up to the eyeballs to shut them up! Real prescribing is more targeted.
The main drugs used in the treatment of depression, anxiety, and OCD are monoamine oxidase inhibitors (MAOIs), tricyclic antidepressants, and selective serotonin reuptake inhibitors (SSRIs).
Antipsychotic drugs can be used to treat schizophrenia by blocking d2 (dopamine) receptors. There are different generations of
antipsychotics:
- Typical antipsychotics – e.g., chlorpromazine, block d2 receptors in several brain
areas. - Less typical antipsychotics – e.g., pimozide, often used as a last resort when other
drugs have failed. - Atypical antipsychotics – e.g., risperidone. Some atypicals also block serotonin
receptors.
Effectiveness
- Established and Effective: Antipsychotics are a relatively cheap, effective treatment that rapidly reduces symptoms, letting many people live relatively normal lives (Van Putten, 1981).
- Relapse Risk: Relapse is likely once drugs are discontinued.
- Better Than No Treatment: Drug treatment is usually superior to no treatment at all.
- Response Rate: Between 50% and 65% of patients benefit from drug treatment.
Appropriateness
- Treats Symptoms, Not Causes: Drugs do not address the underlying cause of the problem; they only reduce symptoms.
- Side Effects: Antipsychotics can cause motor tremors and weight gain, leading some patients to stop treatment.
- Patient Preference: Many patients welcome drug therapy because it is quicker, easier, and less threatening than talk therapy.
- Dependency Risk: Some drugs cause dependency.
- Ethical Concerns: Informed consent and the dehumanising effects of some treatments raise ethical questions.
Electro Convulsive Therapy (ECT)
Electro Convulsive Therapy (ECT) began in the 1930s. Researchers had noticed that when cows are killed by electric shock, they convulse as if having an epileptic seizure.
Doctors tried the idea on humans. The theory: nobody can have schizophrenia and epilepsy together, so inducing epilepsy by shock would force schizophrenic symptoms into submission.
ECT was largely abandoned as a schizophrenia treatment after antipsychotic drugs arrived in the 1950s. It has since been re-introduced in the USA.
In the UK, NICE does not recommend ECT except in particular cases, mainly catatonic schizophrenia. It is sometimes a last resort for severe depression.
ECT can be unilateral (one electrode) or bilateral (electrodes on both temples).
Administering ECT involves a short-acting anesthetic, a muscle relaxant, and oxygen before the shock itself.
A small amount of current (about 0.6 amps) passed through the brain lasting for about half a second. The resulting seizure lasts for about a minute. ECT is usually given three times a week for up to 5 weeks.
ECT should only be used when all else fails! Many argue that this justifies ECT’s use, especially if it prevents suicide. It is generally used in severely depressed patients for whom psychotherapy and medication have failed.
ECT can also help those with schizophrenia and manic depression. Relief is not always permanent, though: Sackheim et al. (1993) found a high relapse rate within a year.
Critics disagree. Its uncontrolled use in large, understaffed institutions can turn ECT into a way to make patients docile, or even a punishment (Breggin 1979).
Side effects include impaired language and memory, plus loss of self-esteem from being unable to recall personal facts or perform routine tasks.
Nobody fully understands how ECT works. Doctors have compared it to kicking the side of an old television to make it work. This adds to why the treatment remains ethically contested, since it often takes place without the individual’s consent.
There are three theories as to how ECT may work:
- Punishment Theory: The shock itself shocks the person out of their illness, working as a kind of punishment for the behaviour.
- Biochemical Theory: Biochemical changes triggered by the shocks stimulate particular neurotransmitters in the brain.
- Fresh-Start Theory: Memory loss from the shock lets the person start afresh, having literally forgotten they were depressed or unwell.
Psychosurgery
As a last result, when drugs and ECT have apparently failed, psychosurgery is an option. This basically involves either cutting out brain nerve fibers or burning parts of the nerves that are thought to be involved in the disorder (when the patient is conscious).
The most common form of psychosurgery is a prefrontal lobotomy.
The Discovery of Lobotomy: Egas Moniz
Unfortunately, these operations have a nasty tendency to leave the patient with a flat personality and shuffling movements, due to their inaccuracy. Moniz “discovered” lobotomy in 1935 after removing bits of chimpanzees’ brains.
His revolutionary treatment was not so perfect. In 1944, a dissatisfied patient shot him in the spine, paralyzing him for life.
As a consolation, he received the Nobel prize for his contribution to science in 1949.
Risks and Decline of Psychosurgery
Surgery is used only as a last resort, when the patient has not responded to other treatment and their disorder is very severe. All surgery carries risk.
The effects of neurosurgery can be unpredictable, and irreversible, with no guarantee of benefit to the patient.
Psychosurgery has scarcely been used to treat schizophrenia since the early 1970s, when drug treatment replaced it.
There are four major types of lobotomy.
BBC Radio 4: The Lobotomists tells the story of three key figures in the strange history of lobotomy. It explores the popularity of lobotomy in the UK for the first time in detail.
Evaluation of The Medical Model
Strengths
- Objective and Scientific: The model is based on established biological science, giving it perceived objectivity compared with moral or social explanations of distress.
- Explains Real Conditions: It has identified genuine organic causes for some conditions, such as GPI and Alzheimer’s disease, which produces confusion in older adults.
- Enables Effective Treatment: Treatment is quick, cheap, and easy to administer, and has controlled illnesses like schizophrenia well enough for many patients to live at home.
- Reduces Some Stigma: Framing disturbance as illness, not badness, has historically reduced fear of people with mental disorders. Earlier moral explanations saw sufferers, especially women, burned as witches.
- Shared Language for Research: A common classification lets clinicians communicate about prognosis and treatment, and lets researchers study comparable groups of patients (Gelder et al., 1989).
Weaknesses:
- Chemical Imbalance Myth: Psychiatric drugs are often prescribed on the assumption that they correct a “chemical imbalance,” yet despite over 40 years of research, no direct evidence confirms this theory.
- Serious Side Effects: Treatments are not always effective and can cause lasting harm. ECT, for example, can cause memory loss, and drugs may simply act as a “chemical straitjacket.”
- No Physical Cause Found: For most disorders, including schizophrenia, genetic or neurochemical explanations remain inconclusive. Many such disorders are labelled “functional,” and the model largely ignores psychological and social causes.
- Labelling Concerns: Szasz argued that, aside from identified brain diseases, most “mental disorders” are really problems of living. Labelling someone mentally ill can lead to discrimination and loss of rights.
- Partial Explanation Only: The medical model has shaped how disturbed people are treated more than any other approach, but most psychologists see it as only a partial, sometimes inappropriate, explanation.
- No Biological Markers: Except for dementia and some rare chromosomal disorders, no known biological cause exists, so no blood test or brain scan can confirm a psychiatric diagnosis independently ( more info).
- Diagnostic Reliability Stalled: The reliability of diagnosing mental disorders has not improved in over 30 years (Aboraya et al., 2006).
- Manuals Reflect Consensus: The DSM and ICD are shaped by clinical consensus and committee voting as much as by objective science, which raises questions about their validity.
- Stigma and Responsibility: Labelling someone as mentally ill removes responsibility for their behaviour, and illness framing can increase, not reduce, stigma and social distance (Corrigan & Watson, 2002).
- Insider Critique from DSM Leadership: As Allen Frances, who chaired the DSM-IV task force, has written, “there is no reason to believe that DSM-5 is safe or scientifically sound” (Frances, 2013a).
Their validity and clinical utility are therefore highly questionable, yet their influence has contributed to an expansive medicalization of human experience. Click here for more info
References
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