In hypersomnia not due to substance or known
physiologic condition, excessive nighttime sleep,
daytime somnolence, or excessive and nonrefreshing
napping are associated with an identifiable
psychiatric diagnosis, which sometimes becomes
apparent only with time and detailed evaluation.
Associated psychiatric conditions may include
mood disorders, somatoform disorders, conversion
disorders, and other psychiatric disturbances.28,29
Affected individuals often demonstrate intense
preoccupation with their symptoms and may miss
substantial amounts of school or work. Sleep diaries
often reveal prolonged bed time in conjunction
with delayed sleep latency and fragmented nighttime
sleep with variable daytime napping. The
condition most commonly presents during early
adulthood. Despite subjective complaints, objective
sleepiness may be diffi cult to document on
MSLTs.