Sleep paralysis in two children with attention deficit hyperactivity disorder

We describe for the first time the presence of SP in two children with ADHD that was associated with the presence of a sinister shadowy "bedroom intruder" that sometimes attacked the sleeper. The "creature" was lurking in the distant dark, slowly approaching and appearing as a dark shadow, similar to the human size and shape. 4 The pathophysiology of SP and the associated hypnagogic hallucinations might be related to a dysfunctional overlap of the REM and waking stages and polysomnographic studies found that individuals who experience SP have shorter REM sleep latencies along with shortened NREM and REM sleep cycles, and fragmentation of REM sleep. 5 Since SP is a common symptom of narcolepsy, we hypothesized that there may be common underlying pathophysiological mechanisms linking narcolepsy and ADHD that might be linked to a dysfunction in the arousal mechanisms present in narcolepsy and in a specific hypo-arousal phenotype of ADHD. 3