Illusions

Specialty: Psychiatry.

• Distorted perceptions
• perceptual deformation of real stimuli
• pathological pareidolias

Why it occurs

• High anxiety states (e.g., illusion of presence due to fear of the dark)
• Post-traumatic stress disorder (perceiving an everyday object as a weapon)
• Acute delirium in the initial phase
• Consumption of hallucinogenic substances or severe sensory deprivation
• Schizotypal personality disorder
• Dementia with Lewy bodies (frequent visual illusions prior to hallucinations formed)

Initial workup

Detailed ophthalmological and auditory examination (to rule out peripheral sensory deficits that promote the illusion); cognitive assessment scale (MoCA); polysomnography if illusions occur in sleep transitions (hypnagogic/hypnopompic); toxic analysis.

Standard management

• Treat the underlying cause. In Lewy body dementia: Donepezil or Rivastigmine — acetylcholinesterase inhibitors, which significantly improve visual illusions and hallucinations
• In schizophrenia or toxic psychosis: Risperidone or Quetiapine.