Introduction To Psychotic Disorders

Also written as Psychosis, Schizophrenia spectrum disorders.

Psychotic disorders are mental illnesses marked by loss of contact with reality, including delusions, hallucinations, and disorganized thinking. Diagnosis relies on clinical criteria and exclusion of medical causes.

Definition and diagnosis

Psychotic disorders are defined by persistent delusions, hallucinations, disorganized speech or behavior, and negative symptoms lasting at least one month, with functional impairment.

• DSM‑5: ≥1 psychotic symptom >1 month, functional decline
• ICD‑11: characteristic psychotic symptoms with duration criteria

Severity and staging

Severity is graded by symptom burden, functional impairment, and risk of harm. Staging ranges from prodrome (attenuated symptoms) to acute episode to chronic residual phase.

• Prodrome: subthreshold symptoms, functional decline
• Acute: full psychosis, may need hospitalization
• Residual: persistent negative symptoms, cognitive deficits

Causes, most likely first

Most cases are idiopathic, but many secondary causes must be ruled out, especially infections and metabolic disorders common in low‑resource settings.

• Primary schizophrenia spectrum (idiopathic)
• Substance‑induced (cannabis, amphetamines)
• Infections: HIV, neurosyphilis, TB meningitis, malaria cerebral
• Metabolic: severe hyponatremia, hepatic encephalopathy
• Autoimmune: anti‑NMDA receptor encephalitis

How it presents

Patients may report hearing voices, hold bizarre beliefs, show disorganized speech, or display catatonic behavior. Negative symptoms include flat affect and social withdrawal.

• Auditory hallucinations are most common
• Delusions often persecutory or grandiose
• Disorganized speech: loose associations, neologisms
• Negative: avolition, anhedonia, alogia

Investigations

Investigations aim to exclude medical mimics and assess baseline health before treatment.

• Complete blood count & metabolic panel: Detect anemia, electrolyte disturbances, renal/hepatic dysfunction; abnormal values may explain psychosis or affect medication choice
• Serum toxicology screen: Identify substance‑induced psychosis; positive result directs withdrawal and specific care
• HIV, syphilis (RPR/TPPA), TB screening (Chest X‑ray, GeneXpert): Rule out infectious causes prevalent in low‑resource areas; positive test mandates targeted antimicrobial therapy
• Brain imaging (CT or MRI) if focal deficits or atypical onset: Detect structural lesions, tumors, or stroke; if unavailable, rely on clinical exam and treat presumptively
• Autoimmune panel (anti‑NMDA receptor antibodies) when rapid onset, seizures, or autonomic instability: Positive result indicates treatable encephalitis; start immunotherapy

Red flags and complications

Certain features signal imminent danger or poor prognosis and require urgent intervention.

• Suicidal or homicidal intent
• Severe catatonia or neuroleptic malignant syndrome risk
• Rapid deterioration, fever, autonomic instability
• Comorbid untreated infection (e.g., TB meningitis)

Management

Treat underlying cause first, then use antipsychotics for symptom control, plus psychosocial support.

• If infection identified → appropriate antimicrobial therapy
• First‑line antipsychotic: atypical agents (e.g., risperidone, olanzapine) for efficacy and lower EPS risk
• Avoid high‑potency typicals in patients with cardiac disease or seizure risk
• Monitor metabolic side effects, QTc, and blood counts
• Add psychosocial interventions: CBT for psychosis, family education, occupational therapy

Follow-up and prevention

Regular review of symptoms, medication side effects, and functional status is essential; relapse prevention focuses on adherence and early warning signs.

• Monthly review for first 6 months, then every 3 months
• Screen for metabolic syndrome each visit
• Educate patient/family on relapse signs and when to seek help

Often confused with

Several conditions mimic psychosis and must be differentiated.

• Severe depression with psychotic features
• Bipolar mania with psychosis
• Delirium from metabolic or infectious causes
• Personality disorder with transient psychotic-like symptoms

Where results can mislead

Certain investigations may be falsely normal, leading to missed diagnoses.

• Early HIV serology may be negative; repeat if high suspicion
• CSF PCR for TB can be negative; consider clinical picture
• Serum electrolytes may appear normal if sampled after aggressive rehydration

Questions an examiner may ask

• List the DSM‑5 criteria for schizophrenia and explain how you would differentiate it from substance‑induced psychosis.
• Describe the investigation pathway for a patient presenting with first‑episode psychosis in a low‑resource setting.
• Explain the rationale for choosing an atypical antipsychotic over a typical one in a patient with cardiac comorbidity.

When to seek help

• Sudden onset of psychosis with fever or neck stiffness
• Severe self‑harm or aggression
• Rapidly worsening confusion or catatonia

Quick questions

Can infections cause psychosis?

Yes; HIV, TB meningitis, neurosyphilis, and malaria can produce psychotic symptoms and must be ruled out.

Why choose atypical antipsychotics first?

They have lower risk of extrapyramidal side effects and treat both positive and negative symptoms.

What is the most important early sign of relapse?

Re‑emergence of mild hallucinations or suspicious thoughts often precedes full relapse.