Delusional confusion of dreaming and reality in narcolepsy.

STUDY OBJECTIVES

We investigated a generally unappreciated feature of the sleep disorder narcolepsy, in which patients mistake the memory of a dream for a real experience and form sustained delusions about significant events.

DESIGN

We interviewed patients with narcolepsy and healthy controls to establish the prevalence of this complaint and identify its predictors.

SETTING

Academic medical centers in Boston, Massachusetts and Leiden, The Netherlands.

PARTICIPANTS

Patients (n = 46) with a diagnosis of narcolepsy with cataplexy, and age-matched healthy healthy controls (n = 41).

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

"Dream delusions" were surprisingly common in narcolepsy and were often striking in their severity. As opposed to fleeting hypnagogic and hypnopompic hallucinations of the sleep/wake transition, dream delusions were false memories induced by the experience of a vivid dream, which led to false beliefs that could persist for days or weeks.

CONCLUSIONS

The delusional confusion of dreamed events with reality is a prominent feature of narcolepsy, and suggests the possibility of source memory deficits in this disorder that have not yet been fully characterized.