Schizophrenia

Schizophrenia is a severe, chronic psychiatric disorder affecting approximately 1% of the general population worldwide. The term itself means a “splitting of psychic functions” — not a split personality, but a fragmentation of thought, perception, emotion, and volition. It is one of the leading causes of disability globally and remains the central diagnosis in psychiatric practice. The illness typically emerges in late adolescence or early adulthood and follows a course that, in many patients, leads to progressive functional decline over time.

Why Does This Happen? (First Principles)

Understanding schizophrenia requires grasping several complementary neurobiological models, none of which alone is sufficient.

💡 FIRST PRINCIPLE: The neurodevelopmental hypothesis proposes that the roots of schizophrenia lie not in the adult brain but in disrupted development during fetal life, particularly the second trimester. Neural dysplasia — abnormal neuronal migration, synaptic formation, and connectivity — creates a brain that is structurally vulnerable. However, the illness does not manifest at birth. Instead, it remains latent through childhood, only emerging after the normal maturational processes of adolescence — myelination and synaptic pruning — unmask the underlying defect. This explains why patients often appear entirely normal as children, with subtle signs (minor physical anomalies, “soft” neurological signs) only detectable in retrospect.

The dopamine hypothesis remains the most clinically relevant model because it directly explains why antipsychotics work. The current understanding is that excessive dopamine neurotransmission in the associative striatum (notably the mesocortical pathway, rather than the mesolimbic pathway as was previously believed) drives the positive symptoms of psychosis — delusions, hallucinations, and disorganised thinking. At the same time, deficient dopaminergic activation in the prefrontal cortex is thought to underlie the cognitive deficits and negative symptoms that are so difficult to treat.

The glutamate hypothesis offers a deeper explanation. NMDA receptor hypofunction is increasingly considered the primary “trait” abnormality in schizophrenia — a fundamental, enduring vulnerability — with the dopamine changes being downstream “state” effects that fluctuate with acute episodes. This model explains why drugs that block NMDA receptors (such as phencyclidine and ketamine) produce a clinical picture remarkably similar to schizophrenia, including both positive and negative symptoms.

Finally, the concept of dysconnectivity views schizophrenia not as a problem with any single brain region or neurotransmitter, but as a disorder of brain connectivity — the coordinated firing of ensembles of neurons across different brain areas is aberrant, leading to the fragmentation of thought, perception, and behaviour that characterises the illness.

Aetiology & Risk Factors

Genetics

Schizophrenia has a heritability of approximately 80%, making it one of the most heritable psychiatric disorders. The inheritance pattern is probably polygenic (many genes of small effect) and genetically heterogeneous (different genetic variants in different families). The lifetime risk increases substantially with closer genetic relatedness to an affected individual:

Relationship	Lifetime Risk
General population	1%
Second-degree relative	5%
Sibling	9%
First-degree relative (overall)	10%
Dizygotic (non-identical) twin	17%
Child with one affected parent	17%
Monozygotic (identical) twin	45–48%
Child with two affected parents	46%

The fact that concordance in identical twins is 45–48% rather than 100% demonstrates that genetics alone is insufficient — environmental factors must also play a role. The most strongly associated copy number variant (CNV) is the 22q11 deletion (velocardiofacial syndrome), which confers a substantially elevated risk.

⚠️ EXAM DETAIL: The 22q11 deletion is the most strongly associated CNV with schizophrenia — this is a favourite viva and MCQ topic.

The “Double Hit” Hypothesis

This model proposes that schizophrenia develops when environmental factors (the “second hit”) precipitate illness in individuals who already carry a genetic predisposition (the “first hit”). Neither the genetic vulnerability nor the environmental exposure alone is sufficient in most cases — both are required.

Environmental Risk Factors

A wide range of environmental factors have been identified, each with a modest but statistically significant contribution to risk:

Prenatal and perinatal factors include obstetric complications (odds ratio [OR] approximately 2; specifically asphyxia, low birth weight, and emergency caesarean section), winter birth (possibly reflecting prenatal viral exposure), and maternal factors such as malnutrition (OR 2) and infections during pregnancy (influenza A2, toxoplasmosis).

Social and developmental factors include urban upbringing (relative risk [RR] 1.9, with the risk increasing in larger cities), low socioeconomic status (explained by two competing hypotheses — “social drift,” where the illness causes downward socioeconomic mobility, and “social residue,” where those with high-risk traits remain in lower social classes), and migration (RR 2.9 for immigrants, with the highest risk in those moving from lower-income or middle-income countries to a minority ethnic status in the host country).

💡 FIRST PRINCIPLE: The social drift versus social residue debate is important to understand. Social drift proposes that schizophrenia itself causes patients to lose jobs and move to poorer areas. Social residue proposes that individuals with genetic and personality vulnerabilities to schizophrenia were already concentrated in lower social strata. Both mechanisms probably contribute.

Substance use is a significant modifiable risk factor. cannabis use carries a relative risk of 2 overall, but this rises to a sixfold increase in heavy users. Tobacco smoking also confers an elevated risk (RR 2.2). Schizotypal personality traits are considered a personality-level risk factor.

Psychosocial factors include significant life events (OR 3.2), childhood trauma and abuse (OR 3), and high expressed emotion (HEE) in the family, which is a particularly important factor in relapse.

Clinical Features

The clinical features of schizophrenia differ markedly depending on the phase of the illness. Understanding this phased progression is essential for both diagnosis and management.

Prodromal Phase

Before the onset of frank psychosis, most patients experience a prodromal phase lasting weeks to months. This phase is characterised by vague, non-specific symptoms: sleep disturbances, irritability, social withdrawal, and preoccupation with odd ideas. These symptoms are easily overlooked or attributed to other causes (depression, adolescent adjustment).

⚠️ EXAM DETAIL: The cardinal feature of the prodromal phase is unexplained functional decline — a drop in academic performance, loss of interest in work, or withdrawal from social activities without an obvious cause. This is the single most important feature to recognise.

Acute Phase (Psychosis)

The acute phase is dominated by positive symptoms — phenomena that are “added” to normal experience:

Delusions are the most prominent positive symptom. Persecutory delusions are the commonest type (the patient believes others are plotting against them), but delusions of reference (events or objects have special significance directed at the patient), delusions of control or passivity (the patient’s actions, feelings, or thoughts are being controlled by an external force), and thought possession phenomena (thought insertion, thought withdrawal, and thought broadcasting) are particularly characteristic. Delusional perception — the attribution of a delusional meaning to a normal perception — is considered a first-rank symptom.

Hallucinations are predominantly auditory. The most characteristic forms are running commentary (a voice narrating the patient’s actions), third-person voices (two or more voices discussing the patient), and thought echo (the patient hears their own thoughts spoken aloud). Visual, tactile, olfactory, and somatic hallucinations can also occur but are less common and should raise suspicion of an organic cause.

Behavioural disorganisation encompasses bizarre behaviour (often occurring in response to hallucinations or delusions), formal thought disorder (loosening of associations, knight’s move thinking, neologisms, incoherence, and irrelevant speech), and catatonia (stupor, strange posturing, negativism, waxy flexibility, and automatic obedience).

Chronic Phase

Over time — particularly after several acute episodes — the illness tends to evolve towards a state dominated by negative symptoms, sometimes called the “defect state.” The negative symptoms are often described using the “Four As”:

• Alogia — a marked decrease in spontaneous speech, with replies that are brief and lacking in content.
• Avolition — a profound loss of motivation and drive (apathy), making it difficult for the patient to initiate or sustain purposeful activity.
• Affective flattening — emotional blunting, where the patient shows little or no emotional response to events that would normally provoke strong feelings.
• Anhedonia — the inability to experience pleasure from activities that were previously enjoyable.

Negative symptoms are the primary determinant of long-term functional disability. Unlike positive symptoms, they respond poorly to current antipsychotic medications. It is important to note that the chronic phase usually follows several acute episodes, but in some patients (particularly the simple schizophrenia subtype), negative symptoms can present from the very beginning without a preceding psychotic episode.

Cognitive Symptoms

Cognitive deficits — affecting semantic memory, working memory, and attention — are a core feature of schizophrenia and are the most important determinant of poor functional outcome. These deficits are present from early in the illness and do not respond well to antipsychotic treatment.

Subtypes

Although subtypes have been removed from the DSM-5, they retain high clinical utility and continue to be used in ICD-10. Understanding them is essential for examinations:

Paranoid schizophrenia is the commonest subtype. It is characterised by prominent persecutory delusions and auditory hallucinations, with the personality remaining relatively well preserved. It tends to have the best prognosis among the subtypes.

Hebephrenic (disorganised) schizophrenia is characterised by prominent thought disorder and affective symptoms — the patient’s behaviour is silly, unpredictable, and fragmented. This subtype carries a poor prognosis because it tends to present early in life with rapid functional decline.

Catatonic schizophrenia features striking motor symptoms — catatonic stupor, excitement, posturing, negativism, and waxy flexibility. This subtype is now rare in industrialised countries, probably because of improved early treatment. Electroconvulsive therapy (ECT) is the first-line treatment for the catatonic subtype.

Simple schizophrenia is characterised by the insidious development of odd behaviour, social withdrawal, and declining performance without any prominent positive symptoms (no delusions, no hallucinations). Diagnosis requires symptoms to be present for at least 1 year.

⚠️ EXAM DETAIL: Simple schizophrenia requires 1 year of symptoms for diagnosis, distinguishing it from the 1-month duration required for other subtypes.

Investigations

Baseline Blood Tests

Every patient with suspected first-episode psychosis should have a comprehensive baseline workup. This includes a full blood count (FBC), fasting blood sugar (FBS), lipid profile, electrocardiogram (ECG), renal function tests, liver function tests, thyroid function tests, and a urine drug screen. The urine drug screen is particularly important to exclude substance-induced-psychosis.

Metabolic Monitoring

Metabolic monitoring deserves special emphasis because 10% of unmedicated first-episode patients already have metabolic syndrome before any antipsychotic is started. Baseline measurements of body mass index (BMI), blood pressure (BP), FBS, and lipids are mandatory before initiating antipsychotic therapy. These parameters must then be monitored regularly throughout treatment (see monitoring table under Management).

Neuroimaging

Computed tomography (CT) or magnetic resonance imaging (MRI) of the brain should be performed in first-episode psychosis to exclude organic causes, as 3.7% of first-episode cases have an identifiable organic cause (such as temporal lobe epilepsy, space-occupying lesions, or neurosyphilis). Classic neuroimaging findings in schizophrenia include enlarged lateral and third ventricles (approximately 30% increase in volume compared to healthy controls), a 2.6% reduction in overall brain volume, and a smaller hippocampus and thalamus.

Rating Scales

The Calgary Depression Scale for Schizophrenia is a validated instrument specifically designed to distinguish depressive symptoms from the negative symptoms of schizophrenia and from the extrapyramidal side effects (EPS) of antipsychotic medication. This distinction is clinically important because the treatment for depression (antidepressants) differs fundamentally from the management of negative symptoms or EPS.

Management

Pharmacological Treatment — Stepwise Approach

The pharmacological management of schizophrenia follows a clear stepwise algorithm. All antipsychotics work primarily by blocking dopamine D2 receptors. Atypical (second-generation) antipsychotics additionally block serotonin 5-HT2A receptors, which is thought to reduce EPS risk and may contribute to some benefit on negative symptoms.

Step 1: First-Line Treatment of Acute Episodes

Atypical antipsychotics are preferred over typical (first-generation) antipsychotics as first-line treatment because of their lower risk of EPS. Treatment should be started at the lower end of the licensed dose range and titrated gradually according to response and tolerability.

⚠️ EXAM DETAIL: Rapid neuroleptisation (loading doses or rapidly escalating doses) is not recommended. If the patient requires sedation during an acute episode, a benzodiazepine should be used alongside the antipsychotic rather than escalating the antipsychotic dose.

For patients who are acutely agitated or refuse oral medication, intramuscular (IM) haloperidol (a typical antipsychotic) or IM olanzapine may be used, potentially in combination with a benzodiazepine for rapid tranquillisation. Baseline BMI, BP, FBS, and lipids should be measured before starting any antipsychotic.

The commonly used atypical antipsychotics, their doses, and key clinical considerations are summarised below:

Drug	Typical Daily Dose	Key Notes
risperidone	2–6 mg	Most widely used; EPS emerge at higher doses; hyperprolactinaemia is common
Olanzapine	5–20 mg	Highest weight gain and metabolic syndrome risk among atypicals (except clozapine); sedating
Quetiapine	300–800 mg	Sedating; low EPS; also used in mood disorders
Aripiprazole	10–30 mg	Partial D2 agonist — lowest metabolic risk; least sedating
Paliperidone	3–12 mg	Active metabolite of risperidone; available as monthly long-acting injectable (LAI)

When atypical antipsychotics are not tolerated or are unavailable, typical antipsychotics may be used:

Drug	Typical Daily Dose	Key Notes
Haloperidol	5–20 mg	High potency — high EPS risk (acute dystonia, parkinsonism, akathisia); IM form available for agitation
Chlorpromazine	200–800 mg	Low potency — more sedating, anticholinergic, postural hypotension; lower EPS
Trifluoperazine	10–30 mg	Moderate potency; EPS common
Fluphenazine	5–20 mg	Also available as depot (decanoate) for maintenance

Step 2: Maintenance Therapy

Once the acute episode has resolved, the critical question is how long to continue antipsychotic treatment. Premature discontinuation carries a very high risk of relapse.

For a first episode, there is some disagreement in the literature about the optimal maintenance duration. ⚡ CONTRADICTION: The Shorter Oxford Textbook recommends 1–2 years of maintenance therapy after a first episode, while Dr. Ajith Jayasekara (Lecture) states at least 3 years. For Sri Lankan examination purposes, the answer should be given as ≥3 years.

For subsequent episodes, maintenance therapy should continue for 2–5 years or longer. After multiple relapses, many clinicians recommend indefinite maintenance, as the risk of relapse increases with each episode. Throughout maintenance, the lowest effective dose should be used — higher doses increase the side effect burden without adding further efficacy.

Depot (long-acting injectable [LAI]) preparations are an important option for patients with poor adherence. They reduce relapse risk by approximately 30% compared with oral medication. Available depot preparations include fluphenazine decanoate, haloperidol decanoate, zuclopenthixol decanoate, and paliperidone palmitate.

⚠️ EXAM DETAIL: Depot antipsychotics should not be used during acute episodes — they cannot be titrated rapidly, and if an adverse reaction occurs, the drug cannot be withdrawn quickly.

Step 3: Treatment-Resistant Schizophrenia

Treatment-resistant schizophrenia is defined as a failure to respond to adequate doses of two different antipsychotics (at least one of which must be an atypical), each given for an adequate duration (typically 6–8 weeks), with documented adherence.

The only drug with proven superior efficacy in treatment-resistant schizophrenia is clozapine. It is effective in approximately one-third of patients who have not responded to other antipsychotics. Clozapine is started at 12.5 mg daily and titrated slowly, with a target trough level of ≥200 µg/L.

Clozapine requires strict haematological monitoring because of the risk of agranulocytosis (incidence 0.8%), a potentially life-threatening reduction in white blood cell count (WBC). FBC must be monitored weekly for 18 weeks, then 4-weekly for the duration of treatment. Clozapine must be discontinued if the total WBC falls below 3.0 × 10⁹/L or the neutrophil count falls below 1.5 × 10⁹/L. Other serious side effects include myocarditis (highest risk in the first 2 months — monitor for chest pain, tachycardia, and fever), seizures (dose-related, especially at trough levels >500 µg/L), substantial weight gain, sialorrhoea (excessive salivation), and constipation (which carries a genuine risk of paralytic ileus and must be managed proactively, often with prophylactic laxatives).

If clozapine alone produces an inadequate response, clozapine augmentation strategies may be tried. These include adding amisulpride or aripiprazole (this is the only clinical situation that justifies antipsychotic polypharmacy), adding lamotrigine, or augmenting with electroconvulsive therapy (ECT).

⚠️ EXAM DETAIL: The only situation where combining two antipsychotics is justified is clozapine augmentation with amisulpride or aripiprazole.

Monitoring During Antipsychotic Therapy

Antipsychotic medications carry a significant metabolic burden that must be monitored systematically:

Parameter	Frequency
BMI, waist circumference	Baseline, then 3–6 monthly
FBS, lipids	Baseline, then 6–12 monthly
ECG	Baseline (especially if using high-dose antipsychotics or in patients with cardiac risk factors)
FBC	Baseline (mandatory weekly monitoring if using clozapine — see above)
EPS (using Abnormal Involuntary Movement Scale [AIMS])	Regularly — especially with typical antipsychotics or high-dose risperidone

Non-Pharmacological Management

Hospitalisation is indicated for patients at risk of suicide or harm to others, during severe relapses, or for first-episode assessment. Treatment should always be provided in the least restrictive setting possible.

Electroconvulsive therapy (ECT) is the first-line treatment for catatonic schizophrenia and may also be used to augment clozapine in treatment-resistant cases.

Family therapy targets high expressed emotion (HEE) — a pattern of critical comments, hostility, and emotional overinvolvement by family members that is strongly associated with relapse. The number needed to treat (NNT) for family therapy to prevent one relapse is 7, making it one of the most effective psychosocial interventions in psychiatry.

Cognitive behavioural therapy (CBT) is used as an adjunct to medication for persistent positive symptoms that have not responded fully to pharmacotherapy. It helps patients develop coping strategies and re-evaluate delusional beliefs.

Psychosocial and occupational rehabilitation is vital in the chronic phase, where negative symptoms and cognitive deficits impair the patient’s ability to function in daily life.

Sri Lanka Context

In Sri Lankan government hospitals, the following antipsychotics are available: risperidone, olanzapine, clozapine, haloperidol, chlorpromazine, and typical depot preparations. Clozapine is available as the gold standard for treatment-resistant cases, and the necessary monitoring protocols (regular FBC) are in place. Severe or chronic cases may be referred to the National Institute of Mental Health, Angoda, the main tertiary referral centre for psychiatric care.

Complications

Schizophrenia is associated with a 3-fold increase in mortality and a reduction in life expectancy of 15–20 years compared to the general population. The leading cause of excess natural death is cardiovascular disease, driven by a combination of antipsychotic-related metabolic effects (weight gain, dyslipidaemia, impaired glucose tolerance), high rates of smoking, poor diet, and sedentary lifestyle.

Suicide is the leading cause of unnatural death. ⚡ CONTRADICTION: The Shorter Oxford Textbook states a 5% lifetime suicide risk, whereas Dr. Ajith Jayasekara (Lecture) states 10%. Whichever figure is used, the risk is substantially elevated, and suicide risk assessment should be a routine part of every clinical encounter.

⚠️ EXAM DETAIL: Schizophrenia mortality is primarily due to cardiovascular disease (natural cause) and suicide (unnatural cause) — this is a frequently tested point.

Prognosis

The long-term outcome of schizophrenia is described by the “Rule of Thirds”: approximately one-third of patients achieve a good recovery, one-third follow a relapsing-remitting course with partial recovery between episodes, and one-third develop a chronic, unremitting illness with progressive functional decline.

Poor Prognostic Indicators

Several factors are associated with a worse outcome: male sex, younger age of onset, insidious onset (as opposed to acute onset), a long duration of untreated psychosis (DUP), prominent negative symptoms and cognitive impairment, poor insight, and high expressed emotion in the family.

Good Prognostic Indicators

Conversely, factors associated with a better prognosis include female sex, being married or employed (reflecting good premorbid adjustment), acute or later onset, prominence of positive or affective symptoms (rather than negative symptoms), short DUP, and good early response to treatment with maintained compliance.

Differential Diagnosis

Condition	Distinguishing Features
mania	Elevated mood, pressured speech, and grandiosity are the dominant features. The psychotic symptoms (if present) are mood-congruent and secondary to the mood disturbance.
psychotic-depression	Low mood, hopelessness, and nihilistic delusions predominate. The Calgary Depression Scale helps distinguish depressive symptoms from negative symptoms and EPS.
substance-induced-psychosis	Temporal relationship with substance use (particularly cannabis, stimulants, and phencyclidine). Psychotic symptoms typically resolve with abstinence, though prolonged use can cause a persistent psychotic disorder.
organic-psychosis	Secondary to a medical condition: temporal lobe epilepsy, neurosyphilis, leukodystrophy, or space-occupying lesions. Neuroimaging and appropriate investigations are essential to exclude organic causes.
delusional-disorder	Non-bizarre delusions without other prominent schizophrenic features (no formal thought disorder, no prominent hallucinations). Personality and functioning are well preserved.
acute-and-transient-psychotic-disorder	Similar psychotic features but duration is less than one month. Onset is typically acute, and full recovery is the rule.
schizoaffective-disorder	Both schizophrenic and affective symptoms are present simultaneously and with similar intensity, making it impossible to classify the episode as purely schizophrenic or purely affective.

Exam Focus

Viva Questions

• What are Schneider’s First Rank Symptoms? (See icd-10-schizophrenia-criteria.)
• What is the lifetime risk for a sibling (9%) vs. an identical twin (45%) of a patient with schizophrenia?
• Define “Expressed Emotion” and its components (critical comments, hostility, emotional overinvolvement).
• How do you distinguish negative symptoms from depression? (Calgary Depression Scale for Schizophrenia.)
• List 3 good prognostic factors. (Female sex, acute onset, good premorbid adjustment.)
• Define treatment-resistant schizophrenia. How do you initiate clozapine? What monitoring is required?
• Why are atypical antipsychotics preferred over typicals? (Lower EPS risk due to additional 5-HT2A receptor blockade.)
• Name 3 depot antipsychotics and their indication. (Fluphenazine, haloperidol, zuclopenthixol decanoate — for poor adherence in maintenance.)

OSCE Scenarios

• Counselling a patient or carer about the risk associated with 22q11 (velocardiofacial syndrome).
• Managing a violent patient: safety, de-escalation, and rapid tranquillisation.
• Explaining clozapine to a patient: starting dose, titration, FBC monitoring schedule, and side effects to watch for (sore throat, fever, constipation).
• Metabolic monitoring: advising a patient on antipsychotic-related weight gain and the need for regular metabolic screening.

MCQ Traps

• ⚠️ EXAM DETAIL: Maintenance therapy after a first episode should be for at least 3 years (local exam guidance).
• ⚠️ EXAM DETAIL: Rapid neuroleptisation (loading doses) is not recommended — use benzodiazepines for sedation instead.
• ⚠️ EXAM DETAIL: Depot antipsychotics are contraindicated in acute episodes because they cannot be titrated rapidly.
• ⚠️ EXAM DETAIL: Clozapine requires FBC monitoring — weekly for 18 weeks, then 4-weekly.
• ⚠️ EXAM DETAIL: The only situation justifying antipsychotic polypharmacy is clozapine augmentation (add amisulpride or aripiprazole).
• ⚠️ EXAM DETAIL: 22q11 deletion is the most strongly associated CNV with schizophrenia.

Source Notes

• Handbook of Clinical Psychiatry (de Silva & Hanwella): Core clinical description, subtypes, management algorithm, pharmacological details.
• Shorter Oxford Textbook of Psychiatry (Harrison et al.): Neurobiological models (dopamine, glutamate, dysconnectivity), genetic risk statistics, neuroimaging findings, prognosis (5% suicide risk, Rule of Thirds), maintenance duration (1–2 years for first episode).
• Schizophrenia and Related Disorders — Dr. Ajith Jayasekara (Lecture, Parts 1 & 2): Social drift/residue hypothesis, “Double hit” aetiology, environmental risk factors with specific OR/RR values, prodromal cardinal feature, maintenance duration (≥3 years for first episode), 10% suicide risk.