Nightmares in narcolepsy: underinvestigated symptom?

Objective: Besides main disease symptoms, disturbing dreams are often found in narcoleptics and may contribute to disturbed sleep. Our main goal was to study different types of oneiric activity in narcolepsy with cataplexy (NC) and narcolepsy without cataplexy (N).

Methods: We have analyzed the medical history of 118 narcoleptics (64 men, 86 with NC, 32 with N, mean age 41.6±15 years). Their most frequent dreams were divided into four groups: (A) low recall/mundane dreams, (B) vivid dreams without disturbing negative emotion, (C) nightmares, (D) reduction of nightmares, possibly by medication. Associations with other features of the disease were statistically analyzed.

Results: Nightmares were found in one-third of the patients, proportionally distributed in N and NC groups; not negatively charged vivid dreams appeared more frequently in NC patients (P<0.005). No/mundane dreams occurred with higher prevalence in men (48%) than in women (20%), (P<0.005), without any significant influence of age. Occurrence of nightmares was significantly higher in patients with REM sleep behavior (P<0.05), but lower in patients with obstructive sleep apnea (P<0.005). Polysomnographic correlation of N and NC nightmare groups showed more wakefulness (P<0.05) and higher percentage of NREM1 stage (P<0.05) in NC patients with nightmares.

Conclusion: Compared with the general population, nightmares seem to be significantly more prevalent in both NC and N, and they are not sufficiently investigated and treated. The neurobiological basis of narcolepsy and patients' dreaming activities appear to be closely related.