Kleine–Levin syndrome

ABSTRACT Kleine–Levin syndrome (KLS) is a rare sleep disorder marked by recurrent hypersomnolent episodes and behavioral changes with unclear etiology. We report a 45-year-old male with severe, early-onset KLS – episodes lasting 20 days and recurring monthly since age 10. Symptoms included hypersomnolence, derealization, hypersexuality, aggression on forced arousal, and interepisode depression. His history includes childhood Attention-Deficit Hyperactivity Disorder (ADHD) and early traumatic brain injury (TBI). Despite trials of various psychotropic medications, symptoms persisted. This case suggests a possible link among ADHD, TBI, and KLS. While ADHD and narcolepsy share neurobiological features – and narcolepsy overlaps with KLS – the role of genetic or neurodevelopmental factors in KLS remains uncertain. The patient’s trajectory raises the hypothesis of an interaction between ADHD, narcolepsy, and KLS, though this may be coincidental. This report contributes to the limited literature on severe, early-onset KLS and underscores the need for further research into potential neurodevelopmental and traumatic risk factors.