Experiencing an occasional sleepless night every now and again is normal and transient insomnia affects all of us from time to time, especially when we are under personal or professional stress, or our schedule changes significantly as a result of jet lag or shift work. But prolonged insomnia, lasting for perhaps six months or more, is another story.If you have been unable to sleep every night, or most nights, for an extended period, then you may well suffer from serious insomnia.If left untreat.