Diagnostic criteria and subtypes

Diagnostic Criteria - The Reality Glitch

• DSM-5: Requires ≥2 of the following symptoms 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) Disorganized speech (e.g., frequent derailment or incoherence)
  • (4) Grossly disorganized or catatonic behavior
  • (5) Negative symptoms
• Duration: Continuous signs of the disturbance must persist for at least 6 months. This 6-month period must include at least 1 month of active-phase symptoms.
• Dysfunction: Level of functioning in one or more major areas (e.g., work, interpersonal relations, or self-care) is markedly below the level achieved prior to onset.
• Exclusions: Rule out schizoaffective disorder, depressive or bipolar disorder with psychotic features, substance-induced psychosis, and psychosis due to another medical condition.

⭐ Impaired functioning is key! Unlike some other psychotic disorders (e.g., delusional disorder), schizophrenia diagnosis requires a significant decline in social or occupational performance.

Symptom Domains - Positives vs. Negatives

• Positive Symptoms: Pathological excesses; behaviors added to the person's repertoire. Linked to ↑ dopamine in the mesolimbic pathway.

  • Delusions: Fixed, false beliefs despite contrary evidence.
  • Hallucinations: Sensory experiences without external stimuli (auditory is most common).
  • Disorganized Speech: Loose associations, tangentiality, word salad.
  • Grossly Disorganized or Catatonic Behavior.

• Negative Symptoms: Pathological deficits; absence of normal behaviors. Linked to ↓ dopamine in the mesocortical pathway.

  • 📌 The 5 A's:
    • Affect (blunted/flat): Diminished emotional expression.
    • Alogia: Poverty of speech.
    • Avolition: Decreased motivation.
    • Anhedonia: Decreased ability to experience pleasure.
    • Asociality: Lack of interest in social interactions.

⭐ Negative symptoms are major contributors to poor functional outcomes and are generally less responsive to antipsychotic medication than positive symptoms.

Schizophrenia Subtypes - Ghosts of Subtypes Past

• The DSM-5 eliminated the classical schizophrenia subtypes. They are no longer used for diagnosis but may appear in older questions or clinical charts.
• Emphasis is now on assessing symptom dimensions (e.g., reality distortion, negative symptoms) for a more precise description.

• Paranoid Type: Preoccupation with one or more delusions (typically persecutory or grandiose) or frequent auditory hallucinations. Cognitive function and affect are relatively preserved.
• Disorganized Type: Characterized by disorganized speech, disorganized behavior, and flat or inappropriate affect.
• Catatonic Type: Dominated by at least two catatonic symptoms (e.g., motor immobility, excessive motor activity, extreme negativism, echolalia/echopraxia).
• Undifferentiated Type: Symptoms meet criterion A for schizophrenia, but the criteria are not met for the Paranoid, Disorganized, or Catatonic Type.
• Residual Type: Absence of prominent delusions, hallucinations, or disorganized speech/behavior. Continuing evidence of the disturbance is indicated by the presence of negative symptoms.

⭐ The primary reason for removing subtypes was their poor diagnostic stability, low reliability, and limited clinical utility in predicting treatment response or course of illness.

High-Yield Points - ⚡ Biggest Takeaways

• Diagnosis requires ≥2 symptoms (one must be delusions, hallucinations, or disorganized speech) for a significant portion of 1 month, with continuous signs for ≥6 months.
• Social or occupational dysfunction is a core diagnostic requirement.
• Negative symptoms (avolition, flat affect, alogia) are crucial for diagnosis and portend a poorer prognosis.
• DSM-5 eliminated subtypes; now use specifiers like "with catatonia".
• Timeline is key: Brief Psychotic Disorder (<1 month), Schizophreniform (1-6 months), Schizophrenia (≥6 months).