Notes · Psychiatry · 11 October 2026

Schizophrenia – Diagnostic Criteria & Management

Definition

• Schizophrenia is a chronic, severe mental disorder characterized by a constellation of positive symptoms (delusions, hallucinations, thought disorder), negative symptoms (affective flattening, alogia, avolition), and cognitive deficits that impair social and occupational functioning.
• Diagnosis is made when symptoms persist for ≥6 months, with at least 1 month of active-phase symptoms, and cause significant distress or dysfunction.

Epidemiology

• Lifetime prevalence: ~0.5–1 % worldwide; similar in India (≈0.4 %).
• Age of onset: males 18–25 y, females 25–35 y (≈3 y later).
• Sex distribution: slightly higher male prevalence; males have earlier onset and poorer premorbid functioning.
• Course: ~20 % achieve remission, 30 % have chronic residual symptoms, 50 % have intermittent relapses.

Aetiology (Multifactorial)

• Genetic:
  • First‑degree relative risk ≈10 × general population.
  • Polygenic risk scores (PRS) explain ~30 % heritability; >100 risk loci identified (e.g., COMT, NRG1, ZNF804A).
• Neurodevelopmental:
  • Prenatal insults (maternal infection, obstetric complications, hypoxia).
  • Perinatal brain injury, early childhood trauma.
• Neurochemical:
  • Dopamine hypothesis: hyperactivity of mesolimbic D2 pathways → positive symptoms; hypoactivity of mesocortical pathways → negative/cognitive symptoms.
  • Glutamate NMDA‑receptor hypofunction and serotonergic dysregulation also implicated.
• Neuroanatomical:
  • Reduced gray‑matter volume (prefrontal cortex, temporal lobes, hippocampus).
  • Enlarged ventricles, cortical thinning.
• Environmental:
  • Urban upbringing, migration, cannabis use (especially high‑THC strains), psychosocial stressors.

Pathophysiology (Integrative Model)

1. Genetic vulnerability → abnormal neurodevelopment.
2. Prenatal/early life insults → altered synaptic pruning, dysregulated dopamine/glutamate circuits.
3. Adolescent stressors (e.g., cannabis) trigger dopaminergic surge in mesolimbic system.
4. Resultant circuit dysfunction leads to:
   • Positive symptoms: excess mesolimbic dopamine → aberrant salience.
   • Negative/cognitive symptoms: prefrontal hypodopaminergia & NMDA‑receptor hypofunction → impaired executive function.

Clinical Features (DSM‑5‑TR / ICD‑10)

Investigations

• Baseline labs (CBC, LFT, renal, fasting glucose, lipid profile) – required before antipsychotic initiation.
• Pregnancy test in women of child‑bearing age.
• ECG – baseline QTc (especially for ziprasidone, thioridazine).
• Neuroimaging (MRI preferred) – to rule out organic causes; may show ventricular enlargement or cortical thinning but not diagnostic.
• Cognitive assessment (e.g., MoCA, BACS) – baseline for monitoring.
• Clozapine monitoring (if indicated): ANC weekly for first 6 months, then bi‑weekly/monthly.
• Substance‑use screening – urine toxicology for cannabis, amphetamines, etc.

Management (Guidelines: Indian Psychiatric Society (IPS) Clinical Practice Guidelines 2022; NICE NG221 2023; APA DSM‑5‑TR 2022)

1. Pharmacotherapy

2. Psychosocial Interventions (IPS 2022)

• Psychoeducation – for patient & family; improves adherence.
• Cognitive‑behavioral therapy for psychosis (CBTp) – reduces delusional conviction, improves insight.
• Social skills training & supported employment – enhances functional recovery.
• Family intervention – reduces relapse rates (RR ≈ 0.5).
• Assertive Community Treatment (ACT) – for high‑risk, non‑adherent patients.

3. Acute Management of Severe Agitation/Excited Catatonia

• Intramuscular (IM) antipsychotic (e.g., Haloperidol 5 mg) ± benzodiazepine (Lorazepam 2 mg).
• Electroconvulsive therapy (ECT) – indicated for refractory catatonia, severe psychosis, or when rapid response needed.

4. Long‑term Maintenance

• Continue antipsychotic at the lowest effective dose for ≥1–2 years after remission; consider dose reduction after ≥5 years of stability if relapse risk low.
• Regular metabolic monitoring (weight, waist, fasting glucose, lipids) every 3–6 months for SGAs.
• Annual physical health review – cardiovascular risk, bone health (especially with long‑term antipsychotics).

5. Special Populations

• Pregnancy: Prefer haloperidol or low‑dose SGAs (e.g., quetiapine) after risk‑benefit discussion.
• Elderly: Start at ½ usual dose; monitor for anticholinergic burden and falls.

Complications

• Medical: Metabolic syndrome, type 2 diabetes, dyslipidemia, cardiovascular disease, obesity, QT prolongation, venous thromboembolism.
• Neurological: Tardive dyskinesia (≈5 % after 5 years of typical antipsychotics), neuroleptic malignant syndrome, catatonia.
• Psychosocial: Stigma, unemployment, homelessness, poor quality of life, increased suicide risk (≈5 % lifetime).
• Clozapine‑specific: Agranulocytosis, myocarditis, seizures, constipation.

High‑Yield Exam Points

• DSM‑5‑TR criteria: ≥2 symptoms (one must be delusions, hallucinations, or disorganized speech) persisting ≥1 month, total duration ≥6 months.
• First‑episode vs. chronic: First‑episode patients respond better to lower antipsychotic doses; higher risk of EPS with FGAs.
• Clozapine indication: Treatment‑resistant schizophrenia (failure of ≥2 antipsychotics) + mandatory ANC monitoring.
• Negative symptoms are primary (intrinsic) vs. secondary (due to depression, medication side‑effects, or social isolation).
• Catatonia – treat with lorazepam 1–2 mg q4‑6 h or ECT if refractory.
• Metabolic monitoring schedule (IPS 2022): baseline, 3 mo, 6 mo, then annually.
• Suicide risk is highest in the first 5 years of illness; clozapine reduces suicidality.
• Differential diagnosis: Mood disorder with psychotic features, substance‑induced psychosis, brief psychotic disorder, schizophreniform disorder.

Practice questions

1. A 22‑year‑old male presents with a 3‑month history of persecutory delusions, auditory hallucinations, and disorganized speech. He has no mood symptoms. Which of the following satisfies the DSM‑5‑TR diagnostic requirement for schizophrenia?
A) Symptoms present for ≥1 month
B) At least two of the five core symptoms, one being delusions, hallucinations, or disorganized speech
C) Absence of substance use in the past 6 months
D) Presence of negative symptoms for ≥6 months

Answer: B — DSM‑5‑TR requires ≥2 core symptoms, with at least one being delusion, hallucination, or disorganized speech.

2. Which antipsychotic is the drug of choice for a patient with treatment‑resistant schizophrenia after two adequate trials of other agents?
A) Risperidone
B) Olanzapine
C) Haloperidol
D) Clozapine

Answer: D — Clozapine is indicated for treatment‑resistant schizophrenia per IPS and NICE guidelines.

3. A patient on olanzapine develops a fasting glucose of 130 mg/dL after 6 months of therapy. According to IPS 2022 recommendations, the next appropriate step is:
A) Switch to a first‑generation antipsychotic
B) Add metformin and continue olanzapine
C) Discontinue olanzapine and start haloperidol
D) No action; monitor only

Answer: B — Metabolic monitoring mandates lifestyle advice and, if glucose is elevated, addition of metformin while considering dose reduction or switch if needed.

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