A 24-year-old unmarried male from Delhi presents to the psychiatry outpatient department with a 6-month history of hearing voices that comment on his actions and converse with each other. His family reports he has become increasingly withdrawn, neglects personal hygiene, and spends hours staring blankly at the wall. He believes that his thoughts are being broadcast on television and that neighbours are plotting against him. Mental status examination reveals poverty of speech, blunted affect, and disorganized thinking. There is no history of substance abuse or medical illness. What is the most likely diagnosis?

Explanation

## Diagnostic Criteria and Differential **Key Point:** The diagnosis of schizophrenia requires the presence of two or more psychotic symptoms for at least 1 month, with continuous signs of disturbance for at least 6 months (including prodromal or residual phases). ### Clinical Features Present in This Case 1. **Positive symptoms** (psychotic features): - Auditory hallucinations (voices commenting and conversing) - Delusions (thought broadcasting, ideas of reference/persecution) 2. **Negative symptoms**: - Social withdrawal - Blunted affect - Poverty of speech - Neglect of self-care 3. **Cognitive/disorganization symptoms**: - Disorganized thinking 4. **Duration**: 6 months of continuous symptoms ### Differential Diagnosis Table | Disorder | Duration | Psychotic Symptoms | Functional Decline | Negative Symptoms | |---|---|---|---|---| | **Schizophrenia** | ≥6 months | ≥2 present | Yes, marked | Often prominent | | Schizophreniform | 1–6 months | ≥2 present | May be absent | Variable | | Brief psychotic | <1 month | ≥1 present | Variable | Minimal | | Delusional disorder | ≥1 month | Non-bizarre delusions only | Minimal | Absent | **High-Yield:** The presence of negative symptoms (blunted affect, poverty of speech, withdrawal) alongside positive symptoms and functional decline lasting 6 months strongly supports schizophrenia over schizophreniform disorder (which requires only 1–6 months). **Clinical Pearl:** In schizophrenia, negative symptoms often emerge during the prodromal phase and persist, whereas in schizophreniform disorder they are less prominent and may resolve quickly even if psychotic symptoms remit. **Mnemonic: PSYCH** — Psychotic symptoms (≥2), Sustained for 6 months, Yoked to functional decline, Cognition/disorganization present, Hallucinations/delusions prominent.