Insomniareferstoadisorderinwhichpatientcannothavenormalorenoughsleep.Clinically,ithasdifferentmanifestations.Inmildcases,itismanifestedasdifficultyingettingtosleep,easytowakeupandunabletosleepagainafterwaking.Inseverecases,itismanifestedassleeplessnessduringthewholenight.