ICD-10 Diagnostic Criteria for Schizophrenia
Purpose
Used to establish a definitive diagnosis of schizophrenia based on symptom clusters and duration.
Criteria
A minimum of one very clear symptom from Group 1, OR symptoms from at least two of the groups in Group 2, present for most of the time during a period of 1 month or more.
Group 1 (Min 1 required)
- Thought echo and alienation: Thought echo, thought insertion/withdrawal, and thought broadcasting.
- Passivity and Delusional Perception: Delusions of control, influence, or passivity; delusional perception.
- Third Person Auditory Hallucinations: Running commentary, voices discussing the patient, or voices coming from a part of the body.
- Bizarre Delusions: Persistent delusions that are culturally inappropriate and completely impossible.
Group 2 (Min 2 required)
- Hallucinations with Delusions: Persistent hallucinations in any modality with fleeting delusions without affective content or with persistent overvalued ideas.
- Formal Thought Disorder: Breaks in the train of thought resulting in incoherence, irrelevant speech, or neologisms.
- Catatonic Behaviour: Excitement, posturing, waxy flexibility, negativism, mutism, stupor.
- Negative Symptoms: Marked apathy, paucity of speech, and blunting or incongruity of emotional responses.
Group 3 (Social/Behavioral Change)
- Significant and consistent change in overall quality of personal behaviour (loss of interest, aimlessness, social withdrawal).
- ⚠️ EXAM DETAIL: For a diagnosis of simple schizophrenia, this 9th criterion is essential and requires a one-year duration.
Exclusions
- Organic Illness: Symptoms must not be due to a brain disease or systemic medical condition.
- Affective Symptoms: Exclude cases with prominent manic or depressive symptoms unless schizophrenic symptoms preceded them.
Duration Requirement
- Symptoms must be present for at least 1 month (except for simple schizophrenia which needs 1 year).
ICD-10 vs DSM-5 Comparison
| Feature | ICD-10 | DSM-5 |
|---|---|---|
| Weight on Symptoms | Emphasizes Schneider’s First-Rank symptoms. | Emphasizes course and functional impairment. |
| Duration | 1 month of active symptoms. | 6 months (including 1 month of active symptoms). |
| Subtypes | Recognizes traditional subtypes (Paranoid, etc.). | Subtypes removed. |
| Schizotypal | Categorized under Schizophrenia spectrum. | Categorized as a Personality Disorder. |
Exam Focus
- Often asked to list 4 “First Rank” symptoms (Group 1).
- ⚠️ EXAM DETAIL: The duration requirement for ICD-10 is 1 month, whereas DSM-5 requires 6 months.
- ⚠️ EXAM DETAIL: Simple schizophrenia requires 1 year of symptoms.
Evidence
- Standardized criteria in ICD-10 (WHO).