Hallucinations, illusions, depersonalization, derealization. Perceptual disturbances span psychosis, trauma, substance use, and medical conditions.
Encounter card
Setting
Targeted screening in every psychiatric encounter; expanded exploration when context suggests psychosis, substance use, trauma, or delirium.
Opening move
Ask directly about hallucinations and dissociative experiences. Distinguish modalities (auditory, visual, tactile, olfactory, gustatory). Distinguish from illusions, intrusive memories, and substance-related phenomena.
Sample language
"Have you heard or seen things that others didn't — voices, sounds, shadows, presences?"
"Are the voices saying anything specific? Are they telling you to do anything?"
"Do you ever feel disconnected from your body, like you're watching yourself from outside?"
"Does the world ever feel unreal or dreamlike?"
Listen for
Modality (auditory more often functional psychosis; visual more often organic/substance; olfactory/tactile suggest organic). Command hallucinations (high-risk content). Insight into hallucinations. Triggers and timing. Substance use temporal relationship.
Common pitfalls
Confusing intrusive trauma memories with hallucinations. Missing dissociative symptoms in patients who don't volunteer them. Not screening for command hallucinations when AVH endorsed. Assuming visual hallucinations are functional psychosis (they often aren't).
Red flags / escalate: Command hallucinations to harm self or others. New visual hallucinations (medical workup indicated). Tactile hallucinations (substance use, delirium, formication). Hallucinations with altered mental status (delirium).
Documentation
Endorses/denies by modality. Quote command content if present. Note insight ("Patient knows the voices aren't real" vs "Patient is convinced others can hear them too").
Real-world reality: Visual or tactile hallucinations should trigger medical workup, but psychiatric services often miss the workup because the symptom is filed as psychiatric. Document the clinical reasoning if medical workup is being deferred.
Visual and tactile hallucinations should prompt medical workup; auditory hallucinations more often reflect functional psychiatric illness.
Warm grey-tinted clinical notebook page, slate gray accent. The five modalities of hallucinations — auditory, visual, tactile, olfactory, gustatory — with differential weighting for each. Margin clusters.
Perceptual disturbances span psychiatric, substance, trauma, and medical conditions. The modality of the hallucination matters substantially for differential diagnosis. Auditory hallucinations are most common in functional psychiatric illness (schizophrenia, severe mood disorders with psychotic features). Visual, tactile, olfactory, and gustatory hallucinations more often suggest organic pathology — substance use, delirium, neurologic disease, medication toxicity.
Visual hallucinations particularly warrant medical workup when they're new in an adult patient. Common organic causes: delirium (any cause), Charles Bonnet syndrome (visual hallucinations in patients with significant vision loss, fully retained insight), Lewy body dementia (well-formed visual hallucinations, often of people or animals, plus parkinsonism), substance intoxication or withdrawal (stimulants, hallucinogens, alcohol withdrawal), seizures (especially temporal lobe), medication effects.
Tactile hallucinations classically suggest substance use — particularly stimulant intoxication ("formication," the sensation of bugs crawling on or under the skin). Also seen in alcohol withdrawal and rarely in primary psychotic disorders.
Olfactory hallucinations deserve neurology consultation. They can be seizure auras (especially temporal lobe), neurodegenerative changes, or rarely primary psychotic. New olfactory hallucinations in an adult are not assumed to be psychiatric until medical workup is negative.
Insight into the hallucination shapes the diagnostic conversation. The bereaved patient who reports sensing the deceased presence — and knows it isn't real — is having a common bereavement experience, not psychosis. The patient who is convinced others can hear what they hear, even though they don't, is in different clinical territory. Charles Bonnet patients have full insight; schizophrenia patients often don't.
Dissociation — depersonalization (feeling outside one's body) and derealization (the world feels unreal) — is a perceptual experience that often accompanies trauma, severe anxiety, substance effects, or normal stress. Pathologic when distressing or impairing; common in milder forms across the population.
Distinguishing functional (psychiatric) from organic (medical/substance) hallucinations — modality, onset, fluctuation, insight, accompanying symptoms. Margin notes on workup triggers.
The anchor
Perceptual disturbances span psychosis, substance use, trauma, and medical conditions. Modality, insight, and context guide differential. Visual and tactile hallucinations especially warrant medical workup.
Depersonalization and derealization — perceptual experiences that may or may not be pathological. Margin clusters on context (trauma, anxiety, substance, normal stress) and when to investigate.
Prove it
A patient reports seeing his deceased wife in the kitchen most mornings since she died 6 months ago. He knows she's not really there but finds it comforting. He has no other psychotic symptoms. How do you classify this?