Schizophrenia
General Psychiatry Article Disclaimer
- DSM-5 criteria or ICD-11 diagnostic requirements are used to structure the Clinical Features and Diagnosis section. The classification system used is selected according to its clarity and suitability for non-specialist learning.
- The criteria are summarised and simplified rather than reproduced in full, while preserving their original diagnostic meaning.
- Where appropriate, a student-friendly pattern-recognition summary is provided to highlight the most clinically and exam-relevant features.
Exam tip (re-psychiatry questions)
- Do not attempt to memorise every DSM-5 or ICD-11 criterion word-for-word. However, it is important to read through the criteria and become familiar with the key symptom clusters, duration thresholds, exclusions, and distinguishing features highlighted in this article.
- Exam questions may not provide every feature required to meet the full diagnostic criteria. Familiarity with the criteria can help one recognise the most likely diagnosis, exclude important alternatives, and narrow the differential diagnosis.
Causes and Risk Factors
The exact cause of schizophrenia is unknown [Ref]
| Category | Description / risk factors |
|---|---|
| Genetic predisposition | Schizophrenia is highly heritable (~81% heritability)
|
| Prenatal and perinatal exposure |
|
| Environmental factors |
|
Pathophysiology
Simplified pathophysiology: [Ref]
- Dopamine excess in the dorsal striatum → +ve symptoms in schizophrenia
- Glutamate and GABA deficit in the prefrontal cortex and hippocampus → -ve symptoms in schizophrenia
Clinical Features and Diagnosis
High-yield pattern recognition for schizophrenia:
- Active phase symptoms
- Positive symptoms – psychosis (e.g. delusions, hallucinations, disorganised speech, abnormal behaviour)
- See the Psychotic Disorders (Psychosis) article for more information on these symptoms
- Negative symptoms (often appear before the onset of positive symptoms), “5As” grouped under 2 groups [Ref]
- Diminished emotional expression
- Affect blunted – reduced emotional expression, characterised by reduced facial expressions, poor eye contact, monotonous speech, reduced use of gestures
- Alogia – poverty of speech characterised by a reduction in the quantity or spontaneous content of speech
- Avolition
- Avolition – reduced initiation, self-motivation, and persistence in goal-directed, purposeful activities (e.g. poor grooming/hygiene, withdrawing from work or school)
- Asociality – reduced social interactions and initiative, due to reduced interest in forming relationships with others
- Anhedonia – inability to experience pleasure (NB patients with schizophrenia retain the ability to experience consummatory pleasure but have a profound deficit in anticipatory pleasure, reducing drive in pursuing goal-directed behaviour)
- Diminished emotional expression
- Positive symptoms – psychosis (e.g. delusions, hallucinations, disorganised speech, abnormal behaviour)
- Functional impairment
- Duration: ≥6 months with at least 1 month of active-phase symptoms
DSM-5 criteria for schizophrenia, ALL must be met: [Ref]
| Diagnostic criteria | Description |
|---|---|
| Characteristic symptoms (“active-phase symptoms”) | At least 2 of the following, and at least 1 from points 1-3:
|
| Functional impairment | For a significant portion of the time since the onset of the disturbance, level of functioning in one or more major areas, such as work, interpersonal relations, or self-care, is markedly below the level achieved prior to the onset
Or when the onset is in childhood or adolescence, there is failure to achieve expected level of interpersonal, academic, or occupational functioning |
| Duration | Continuous signs of disturbance for at least 6 months
Within the 6-month period, there must be at least 1 month of active-phase symptoms (i.e. meeting the row 1 criteria) |
| Exclusion | The following have been excluded:
The disturbance is not attributable to the physiological effects of a substance (e.g., a drug of abuse, a medication) or another medical condition |
| Relationship to autism or communication disorder | If there is a history of autism spectrum disorder or a communication disorder of childhood onset, the additional diagnosis of schizophrenia is made only if prominent delusions or hallucinations, in addition to the other required symptoms of schizophrenia, are also present for at least 1 month |
Complications
| Category | Description |
|---|---|
| Mortality and suicide |
|
| Psychiatric comorbidities | Schizophrenia has a strong bidirectional relationship with other mental health conditions
Increased risk of developing:
|
| Medical comorbidities | Increased risk of:
Primarily caused by poor lifestyle factors (e.g. smoking, poor diet, sedentary lifestyle) and antipsychotic-related adverse effects |
Differential Diagnosis: Schizophrenia Spectrum and Related Disorders
Primary psychotic disorders: [Ref]
| Disorder | High-yield distinguishing features |
|---|---|
| Schizophrenia |
|
| Schizophreniform disorder |
|
| Schizoaffective disorder |
|
| Brief psychotic disorder |
|
| Delusional disorder |
|
Important mimics / differentials: [Ref1][Ref2]
| Disorder | High-yield distinguishing features |
|---|---|
| Substance / medication-induced psychotic disorder (drug-induced psychosis) |
|
| Psychotic disorder due to another medical condition (secondary / organic psychosis) | New psychosis (esp. prominent visual hallucinations) + neurological / systemic abnormalities or atypical presentation → consider secondary / organic psychosis
Key causes:
|
| Mania with psychotic features (bipolar disorder) |
|
| Schizotypal personality disorder |
|
| Schizoid personality disorder |
|
Management
Preventing Psychosis (At Risk Patients)
| Indication | Individuals who are distressed + have a decline in social functioning + any of the following
|
| Prevention approach | Refer to specialist mental health service
Do NOT offer antipsychotics to prevent the development of psychosis |
Managing First Episode Psychosis
First episode psychosis must be assessed by and managed in secondary care. Antipsychotics should not be started in primary care.
Core treatment:
- Psychological interventions (both individual CBT and family intervention), PLUS
- Oral antipsychotic monotherapy
Consider group art therapy to help manage negative symptoms and promote recovery
Further information on antipsychotic choice:
| 1st line choice of antipsychotic | NICE did NOT recommend a single preferred 1st line antipsychotic
|
| Escalating antipsychotic treatment | Before escalating antipsychotic therapy, always:
Escalation pathway:
|
Antipsychotic depots are long-acting injectables (usually IM injections) that can be considered if:
- Patient prefers the method of administration, or
- To avoid non-adherence
See the Antipsychotic Pharmacology for more information on antipsychotics (including 1st generation vs 2nd generation, side effects, monitoring)