Insomnia that lasts three months or longer and happens at least three nights a week is considered chronic. Poor sleep habits, such as bedtime rituals that fail to signal your body to get ready for sleep or a sleep schedule that is out of sync with your biological clock, are one potential contributing factor to chronic insomnia. Acute insomnia is a type of short-term insomnia that often only lasts a few days or weeks. This kind of insomnia is typically brought on by stressful life events like divorce, the death of a loved one, losing a job, or an impending big test.