Memory complaints and altered states of consciousness with automatic behaviour of narcoleptic patients indicate cognitive dysfunctioning. Although more problems arise while performing attention tasks than memory tasks, the neuropsychological test inquiry doesn't indicate one particular neuropsychological function as consistently impaired. They often perform well because they compensate impaired wakefulness by an increased willingness to respond. Neurophysiological research indicates that the sometimes occurring cognitive dysfunction is associated with a waxing and waning between wakefulness and sleep. The increased psychopathology is partly a reflection of, partly a reaction to the symptoms. The impact of hypersomnia on psychosocial functioning is more important than that of epilepsy in epileptics. In severe cases smoking and driving should better be dissuaded.