Schizophrenia

Schizophrenia is a chronic, severe psychotic disorder characterised by disturbances in thought, perception, emotion and behaviour, with preserved clear consciousness and (usually) intact orientation. It is the single most heavily examined psychiatry topic in NEET PG, cutting across phenomenology, classification, neurobiology and pharmacology — so a tight grip on every sub-area pays disproportionate dividends.

Definition and core concept

Schizophrenia (Greek: schizo = split, phrenia = mind) is a misnomer — it denotes a split between thought, emotion and behaviour (a "splitting of psychic functions" as Eugen Bleuler described), NOT a split personality (that is dissociative identity disorder). The term was coined by Bleuler in 1911; the earlier term "dementia praecox" was given by Emil Kraepelin, who emphasised its early onset and deteriorating course.

High-yield: "Schizophrenia" → Bleuler. "Dementia praecox" → Kraepelin. "First-rank symptoms" → Kurt Schneider. These three eponym pairings are perennial single-best-answer questions.

Bleuler's 4 A's (fundamental symptoms) are a classic mnemonic:

• Association loosening (formal thought disorder)
• Affect (blunted/inappropriate)
• Ambivalence
• Autism (withdrawal into inner fantasy world)

To these, some add a 5th and 6th A — Attention deficit and Abulia (lack of will).

Epidemiology

Parameter	Key fact
Lifetime prevalence	~1% (0.5–1%) worldwide, remarkably uniform across cultures
Sex ratio	Equal overall (M = F)
Age of onset (males)	15–25 years (earlier, often worse prognosis)
Age of onset (females)	25–35 years; second peak after 40 (bimodal)
Socioeconomic class	Over-represented in lower classes (downward drift hypothesis)
Season of birth	Excess winter/early-spring births
Suicide risk	~5–10% lifetime; leading cause of premature death

High-yield: Lifetime prevalence of schizophrenia ≈ 1%. Concordance in monozygotic twins ≈ 50%; risk in child of two affected parents ≈ 40%; sibling risk ≈ 10%.

Etiology and pathophysiology

Genetics

Strong heritability (~80%). Risk rises with genetic loading — general population 1% → sibling/dizygotic twin 8–12% → child of one affected parent 12% → monozygotic twin or child of two affected parents 40–50%.

Neurochemical hypotheses

1. Dopamine hypothesis (most tested): Schizophrenia results from dopaminergic hyperactivity in the mesolimbic pathway (→ positive symptoms) and dopaminergic hypoactivity in the mesocortical pathway (→ negative/cognitive symptoms). Evidence:

• Amphetamine and levodopa (dopamine agonists) worsen/precipitate psychosis.
• Antipsychotic potency correlates with D2 receptor blockade affinity.

2. Other neurotransmitters: Glutamate (NMDA) hypofunction — PCP and ketamine (NMDA antagonists) reproduce both positive AND negative symptoms, making this the best chemical model. Serotonin (5-HT2A) is the basis of atypical antipsychotic action.

The four dopaminergic pathways are heavily tested:

Pathway	Function	Effect of D2 blockade
Mesolimbic	Positive symptoms (hyperactive)	Therapeutic (antipsychotic effect)
Mesocortical	Negative/cognitive symptoms (hypoactive)	May worsen negative symptoms
Nigrostriatal	Motor control	Extrapyramidal side effects (EPS)
Tuberoinfundibular	Inhibits prolactin	Hyperprolactinaemia (galactorrhoea, amenorrhoea)

High-yield: Blockade of the nigrostriatal pathway → EPS; blockade of the tuberoinfundibular pathway → hyperprolactinaemia. This explains the side-effect profile of typical antipsychotics.

Neurodevelopmental and structural findings

• Lateral and third ventricular enlargement (most consistent CT/MRI finding).
• Reduced grey matter, especially in frontal and temporal (hippocampus) regions.
• Hypofrontality — reduced prefrontal activity on functional imaging.
• Obstetric complications, second-trimester maternal influenza, and winter birth implicate early neurodevelopmental insult.

Clinical features

Positive vs negative symptoms

Positive symptoms ("added on")	Negative symptoms ("taken away")
Delusions	Affective flattening/blunting
Hallucinations (esp. auditory)	Alogia (poverty of speech)
Disorganised speech (formal thought disorder)	Avolition/apathy
Grossly disorganised/catatonic behaviour	Anhedonia
	Asociality (social withdrawal)
Respond well to antipsychotics	Respond poorly; better with atypicals
Linked to mesolimbic dopamine excess	Linked to mesocortical dopamine deficit

Mnemonic for negative symptoms — the 5 A's: Affective flattening, Alogia, Avolition, Anhedonia, Asociality.

Schneider's First-Rank Symptoms (FRS)

Kurt Schneider's FRS, though NOT pathognomonic and NOT required by DSM-5, remain the most frequently tested phenomenology in NEET PG. Mnemonic: "ABCD" — Audible thoughts, Broadcasting of thought, Controlled/made phenomena, Delusional perception.

The full list:

1. Audible thoughts (thought echo / gedankenlautwerden) — hearing one's own thoughts spoken aloud.
2. Voices arguing or discussing in the third person.
3. Voices commenting on one's actions (running commentary).
4. Thought withdrawal, insertion, broadcasting (disorders of thought possession).
5. Made/passivity phenomena — made feelings, made impulses, made volitional acts; "somatic passivity" (bodily sensations imposed by an external agency).
6. Delusional perception — a real perception given an abnormal, highly personal delusional meaning (a two-stage phenomenon).

High-yield: Delusional perception = a normal perception + delusional interpretation in two stages (e.g., "the traffic light turned green, so I knew I was the chosen one"). It is the FRS most often asked to be identified from a clinical vignette.

Characteristic perceptual and thought disturbances

• Hallucinations: Auditory are commonest in schizophrenia (third-person commentary). Visual hallucinations should prompt a search for an organic cause/delirium.
• Thought disorder: Loosening of associations, derailment, tangentiality, neologisms, word salad, thought block.
• Delusions: Often bizarre — persecutory (commonest), delusions of control, reference, grandeur.

DSM-5 diagnostic criteria

Criterion A: Two (or more) of the following, each present for a significant portion of time during a 1-month period; at least one must be (1), (2) or (3):

1. Delusions
2. Hallucinations
3. Disorganised speech
4. Grossly disorganised or catatonic behaviour
5. Negative symptoms

Criterion B: Significant decline in functioning (work, relationships, self-care).

Criterion C — duration: Continuous signs persist for ≥ 6 months, including ≥ 1 month of active (Criterion A) symptoms.

Criteria D & E: Schizoaffective and mood disorders excluded; not attributable to a substance or another medical condition.

High-yield: DSM-5 requires 6-month total duration (≥1 month active symptoms). ICD-11/ICD-10 require only 1 month. Differentiate from brief psychotic disorder (<1 month) and schizophreniform disorder (1–6 months).

Duration-based diagnostic flow: Symptoms <1 month → Brief psychotic disorder → 1–6 months → Schizophreniform disorder → ≥6 months → Schizophrenia.

Subtypes (classical / ICD-10)

DSM-5 abolished subtypes, but ICD-10 subtypes are still examined:

Subtype	Hallmark
Paranoid	Commonest; prominent delusions (persecutory/grandiose) and hallucinations; relatively preserved cognition; best prognosis
Hebephrenic / Disorganised	Disorganised speech & behaviour, inappropriate/silly affect; early onset; worst prognosis
Catatonic	Psychomotor disturbance — stupor, rigidity, posturing, waxy flexibility, negativism
Undifferentiated	Meets criteria but fits no single subtype
Residual	Negative symptoms predominate after an acute episode
Simple	Insidious negative symptoms without florid positive symptoms

Catatonic signs (high-yield): waxy flexibility (cerea flexibilitas), echolalia (repeating speech), echopraxia (mimicking movements), negativism, automatic obedience, ambitendency, mannerisms, and mitgehen/mitmachen.

Diagnosis and investigations

Schizophrenia is a clinical diagnosis (history + mental state examination). There is no confirmatory lab test. Investigations exist to exclude organic causes:

• MRI/CT brain — exclude tumour, vascular lesion (and may show ventricular enlargement).
• Thyroid function, B12, serum calcium, autoimmune screen.
• Urine drug screen (rule out amphetamine, cannabis, PCP-induced psychosis).
• EEG if seizure/encephalitis suspected; consider anti-NMDA-receptor encephalitis antibodies in atypical new-onset psychosis with neurological signs.

Management and drug of choice

Pharmacotherapy overview

Class	Mechanism	Examples	Best for
Typical (1st-gen)	Strong D2 blockade	Haloperidol, chlorpromazine, fluphenazine, trifluoperazine	Positive symptoms; cheap; high EPS
Atypical (2nd-gen)	5-HT2A + D2 blockade	Risperidone, olanzapine, quetiapine, aripiprazole, clozapine	Positive and negative symptoms; low EPS; metabolic side effects

High-yield: Atypical (second-generation) antipsychotics are first-line for a new diagnosis because of fewer EPS and better effect on negative symptoms. Risperidone and olanzapine are common first choices.

Clozapine — the special drug

• Drug of choice for treatment-resistant schizophrenia (failure of ≥2 adequate antipsychotic trials).
• Most effective antipsychotic overall; uniquely reduces suicidality.
• Agranulocytosis (~1%) → mandatory regular WBC/ANC monitoring (weekly initially).
• Other adverse effects: seizures (dose-related), myocarditis, weight gain, sialorrhoea (paradoxical hypersalivation), constipation.
• Causes little or no EPS and does not raise prolactin.

High-yield: Treatment-resistant schizophrenia → clozapine, but monitor for agranulocytosis (CBC). Clozapine is NOT first-line precisely because of this risk.

Extrapyramidal side effects (EPS) — temporal sequence

A favourite exam table:

EPS	Onset	Management
Acute dystonia (oculogyric crisis, torticollis)	Hours–days	Anticholinergics (benztropine/promethazine) or IM diphenhydramine
Akathisia (motor restlessness)	Days–weeks	Beta-blocker (propranolol), benzodiazepine; reduce dose
Parkinsonism (tremor, rigidity, bradykinesia)	Weeks	Anticholinergics; switch to atypical
Tardive dyskinesia (orofacial choreoathetosis)	Months–years	Stop/switch offending drug; VMAT2 inhibitors (valbenazine, tetrabenazine); often irreversible

Neuroleptic Malignant Syndrome (NMS)

A psychiatric emergency from D2 blockade. Tetrad: hyperthermia, "lead-pipe" rigidity, autonomic instability, altered mental state; raised CPK and leucocytosis. Treatment: stop antipsychotic, supportive cooling, dantrolene, bromocriptine.

High-yield: NMS → raised CPK + lead-pipe rigidity + fever; treat with dantrolene/bromocriptine. Contrast with serotonin syndrome (hyperreflexia, clonus, rapid onset).

Non-pharmacological and overall plan

Stepwise approach: Acute episode → atypical antipsychotic (4–6 week trial) → if response, continue ≥1–2 years (first episode) → if non-response after 2 adequate trials → clozapine → add psychosocial measures (family therapy, CBT for psychosis, social skills training, supported employment) throughout. Long-acting injectable (depot) antipsychotics (e.g., paliperidone, fluphenazine decanoate) are used for non-adherence. ECT is reserved for catatonia and treatment-resistant cases.

Course and prognosis

The "rule of thirds": roughly one-third recover substantially, one-third have a relapsing course with partial recovery, and one-third deteriorate chronically.

Good prognosis	Poor prognosis
Acute/sudden onset	Insidious onset
Late onset	Early (childhood/adolescent) onset
Clear precipitating factor	No precipitant
Good premorbid functioning	Poor premorbid adjustment
Prominent positive/mood symptoms	Prominent negative symptoms
Married, good support	Single, withdrawn
Family history of mood disorder	Family history of schizophrenia
Paranoid subtype	Hebephrenic/disorganised subtype

High-yield: Negative symptoms and insidious onset = poor prognosis. A prominent affective component and acute onset = better prognosis.

Complications

• Suicide (5–10% lifetime) — leading cause of early death; risk highest early in illness and in depressed/insightful patients.
• Substance abuse (especially nicotine, cannabis, alcohol) — very common comorbidity.
• Metabolic syndrome from atypicals (weight gain, diabetes, dyslipidaemia — worst with olanzapine and clozapine).
• Social decline, unemployment, homelessness.
• Increased cardiovascular and overall medical mortality (life expectancy reduced ~15–20 years).
• Tardive dyskinesia and other treatment-related morbidity.

Key differentials

Differential	Distinguishing feature
Schizophreniform disorder	Identical symptoms, duration 1–6 months
Brief psychotic disorder	Duration <1 month, full return to baseline
Schizoaffective disorder	Mood episode + psychosis, but ≥2 weeks of psychosis without prominent mood symptoms
Mood disorder with psychotic features	Psychosis occurs only during mood episodes (mood-congruent)
Delusional disorder	Non-bizarre delusion, functioning otherwise preserved, no prominent hallucinations
Substance/medication-induced psychosis	Temporal link to substance (amphetamine, cannabis, steroids)
Organic/secondary psychosis	Delirium, temporal lobe epilepsy, anti-NMDA encephalitis, SLE, Wilson's, B12 deficiency — suspect with visual hallucinations, clouded consciousness, abnormal neurology

High-yield: Schizoaffective vs mood disorder with psychosis: in schizoaffective, psychotic symptoms persist for ≥2 weeks in the absence of a mood episode. If psychosis is confined to mood episodes → mood disorder with psychotic features.

Recently asked / exam angle

• Identify the FRS from a vignette — delusional perception, thought broadcasting and made phenomena are favourites.
• Eponyms: match Bleuler (4 A's / coined the term), Kraepelin (dementia praecox), Schneider (FRS).
• Dopamine pathways linked to therapeutic effect vs side effects (nigrostriatal → EPS, tuberoinfundibular → prolactin).
• Drug of choice for treatment-resistant schizophrenia = clozapine, plus its agranulocytosis monitoring — repeatedly tested.
• EPS sequence: acute dystonia → akathisia → parkinsonism → tardive dyskinesia (with management of each).
• NMS features and treatment (dantrolene/bromocriptine; raised CPK).
• Duration criteria distinguishing brief psychotic / schizophreniform / schizophrenia.
• Most consistent neuroimaging finding = lateral ventricular enlargement.
• Best prognosis subtype = paranoid; worst = hebephrenic.
• Catatonic signs — waxy flexibility, echolalia, echopraxia, automatic obedience.

Rapid revision

1. Term "schizophrenia" → Bleuler; "dementia praecox" → Kraepelin; FRS → Schneider.
2. Lifetime prevalence ≈ 1%; monozygotic twin concordance ≈ 50%.
3. Bleuler's 4 A's: Association loosening, Affect, Ambivalence, Autism.
4. Auditory hallucinations commonest; visual → think organic cause.
5. Delusional perception = real perception + delusional meaning (two-stage) — classic FRS.
6. DSM-5 needs ≥6 months total (≥1 month active); ICD needs 1 month.
7. <1 month = brief psychotic; 1–6 months = schizophreniform; ≥6 months = schizophrenia.
8. Mesolimbic DA excess → positive symptoms; mesocortical DA deficit → negative symptoms.
9. Nigrostriatal block → EPS; tuberoinfundibular block → hyperprolactinaemia.
10. First-line = atypical antipsychotics; treatment-resistant → clozapine (watch agranulocytosis).
11. NMS = fever + lead-pipe rigidity + raised CPK → dantrolene/bromocriptine.
12. Negative symptoms + insidious onset = poor prognosis; paranoid subtype = best, hebephrenic = worst.