Ferndale Insomnia: Insomnia is a sleep disorder in which you have trouble falling and staying asleep. The condition can be short-term (acute) or can last a long time (chronic). It may also come and go. Acute insomnia lasts from 1 night to a few weeks. Insomnia is chronic when it happens at least three nights a week for three months or more. Insomnia is a sleep disorder in which you have trouble falling and staying asleep. The condition can be short-term (acute) or can last a long time (chronic). It may also come and go. Acute insomnia lasts from 1 night to a few weeks. Insomnia is chronic when it happens at least three nights a week for three months or more.