Learning Objective:
By the end of this session, medical students will be able to define psychosis, identify its core features (delusions, hallucinations, disorganized thought), differentiate types of hallucinations, and distinguish psychotic phenomena from illusions in clinical scenarios.
Overview
Psychosis is a mental state characterized by a distorted perception of reality, manifesting as:
- Delusions
- Hallucinations
- Disorganized thought or speech
Psychosis may occur in:
- Primary psychiatric illness (e.g., schizophrenia, bipolar disorder)
- Medical conditions (e.g., neurological disorders, endocrine disorders)
- Substance/medication-induced states
Delusions
Definition: False, fixed beliefs that persist despite evidence to the contrary and are not culturally or religiously typical.
| Type | Clinical Example |
|---|---|
| Erotomanic | Belief that a famous person is in love with them |
| Grandiose | Belief in exceptional talent, wealth, or fame |
| Jealous | Belief that the partner is unfaithful without reason |
| Persecutory | Belief of being conspired against or harmed |
| Somatic | Belief in a bodily abnormality or disease |
| Mixed | Multiple delusion types simultaneously |
| Unspecified | Delusions not fitting other categories |
Key Point: Delusions are idiosyncratic and persistent, unlike transient beliefs.
Disorganized Thought and Speech
Definition: Thought process disturbances causing incoherent or illogical speech.
- Word salad: Random, incoherent words
- Tangential speech: Answers deviate from the question but remain loosely related
- Loose associations: Shifts between unrelated topics
Key Point: Disorganized thought reflects underlying cognitive processing abnormalities.
Hallucinations
Definition: Perceptions without external stimuli.
| Type | Typical Clinical Context |
|---|---|
| Auditory | Common in schizophrenia: hearing voices |
| Visual | Neurologic disorders (dementia, delirium), intoxication |
| Tactile | Alcohol withdrawal, stimulant use (e.g., “cocaine crawlies”) |
| Olfactory | Temporal lobe epilepsy, brain tumors |
| Gustatory | Rare, seen in epilepsy |
| Hypnagogic | Occurs when falling asleep; sometimes in narcolepsy |
| Hypnopompic | Occurs when waking up, sometimes in narcolepsy |
Key Point: Distinguish hallucinations from illusions, which are misinterpretations of real external stimuli (e.g., mistaking a shadow for a cat).
Clinical Pearls
- Auditory hallucinations → more likely psychiatric
- Visual hallucinations → more likely neurologic or substance-related
- Psychotic features may overlap; always consider medical mimics
