Schizophrenia: symptoms and features

Positive and negative symptoms

• Positive symptoms are experiences added to normal functioning: hallucinations (perceiving something that is not there, most often hearing voices), delusions (fixed false beliefs, such as being persecuted or controlled), disordered thinking (speech that jumps between unconnected ideas) and thought insertion (the experience that thoughts have been put into one's mind by an outside force).
• Negative symptoms are losses of normal functioning: reduced motivation (avolition), flattened emotional expression, reduced speech, social withdrawal.

Negative symptoms often respond less well to drug treatment.

First-rank and second-rank symptoms

Kurt Schneider described first-rank symptoms he thought especially typical of schizophrenia:

• voices repeating, commenting on or arguing about the person
• thought insertion, thought withdrawal and thought broadcasting
• passivity experiences (actions or feelings controlled by an outside agency)
• delusional perception (a normal perception given a special meaning).

Other symptoms (such as other hallucinations, flattened emotion or confusion) are second-rank. A Cochrane review (Soares-Weiser et al., 2015) found first-rank symptoms are a useful quick indicator but miss many people whom specialists diagnose with schizophrenia (sensitivity about 60%), and modern manuals do not depend on them.

Diagnostic criteria

Features

• WHO figures: about 1 in 300 people worldwide (about 27 million people), and 1 in 206 adults aged 20 and over (0.49%).
• Only about four in ten people with psychosis receive formal mental health care (WHO).
• The component guide asks you to consider age, gender and ethnicity in diagnosis rates and geographical differences; Suzuki et al. (2014) shows how features (such as underweight) can differ by culture.
• The ICD-11 duration (1 month) is shorter than DSM-5's (6 months), so a person could meet ICD-11 but not DSM-5 criteria: one reason diagnosis differs between systems.

Worked example

Sam believes his neighbours have placed thoughts in his head and hears a voice commenting on what he does. He has felt this way for 7 weeks. Would he meet DSM-5 and ICD-11 criteria?

1. Symptoms: thought insertion (a delusion of control) and a hallucination (a commenting voice): two symptoms, including at least one core symptom.
2. ICD-11 needs at least 1 month: 7 weeks is enough.
3. DSM-5 needs signs for at least 6 months in total: 7 weeks is not enough, so DSM-5 would not yet diagnose schizophrenia (a shorter psychotic disorder might be considered).

Answer: He could meet ICD-11 criteria now but not DSM-5's 6-month duration requirement.

Check yourself

1. What is thought insertion?
   • Hearing a voice that is not there
   • Speech that jumps between unrelated topics
   • A lack of motivation
   • The experience that thoughts have been placed in one's mind by an outside force
   Show answer

   The experience that thoughts have been placed in one's mind by an outside force. Thought insertion is a first-rank symptom: thoughts feel put there from outside.

2. Which is a negative symptom of schizophrenia?
   • Auditory hallucinations
   • Avolition (reduced motivation)
   • Delusions of persecution
   • Thought broadcasting
   Show answer

   Avolition (reduced motivation). Negative symptoms are losses of normal function.

3. DSM-5 requires continuous signs of schizophrenia for at least how many months?
   Show answer

   6 months. At least 6 months in total, including at least 1 month of active symptoms.

4. WHO estimates schizophrenia affects 1 in 300 people. What percentage is that? Give your answer to 2 decimal places.
   Show answer

   0.33 %. 1 / 300 x 100 = 0.33%.

5. Under DSM-5, at least one of the two required symptoms must be
   • negative symptoms
   • catatonic behaviour
   • delusions, hallucinations or disorganised speech
   • social withdrawal
   Show answer

   delusions, hallucinations or disorganised speech. One must be a core positive symptom: delusions, hallucinations or disorganised speech.

6. Explain why the same person might be diagnosed with schizophrenia under ICD-11 but not under DSM-5.
   Show answer

   ICD-11 only requires symptoms for at least one month, while DSM-5 requires signs for at least six months, so someone with two months of symptoms meets ICD-11 but not DSM-5 criteria.. The duration requirement differs: 1 month (ICD-11) versus 6 months (DSM-5).

7. Which is one of Schneider's first-rank symptoms?
   • Low mood for two weeks
   • Fear of gaining weight
   • Voices commenting on the person's actions
   • Poor concentration
   Show answer

   Voices commenting on the person's actions. Commenting voices are a first-rank symptom.

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Sources

• Pearson Edexcel International Advanced Subsidiary/Advanced Level in Psychology specification (issue January 2026)
• Pearson IAL Psychology component guide: WPS04 (Issue 2, November 2024)
• American Psychiatric Association: highlights of changes from DSM-IV-TR to DSM-5 (schizophrenia criteria)
• WHO ICD-11 for Mortality and Morbidity Statistics: 6A20 Schizophrenia
• Soares-Weiser et al. (2015), First rank symptoms for schizophrenia, Cochrane Database of Systematic Reviews
• WHO fact sheet: Mental disorders (Global Burden of Disease figures for 2023)
• WHO fact sheet: Schizophrenia
• Pearson IAL Psychology summary of studies: WPS04

Last updated 8 November 2026. Spotted a mistake? Tell us.