Sleep requirements vary from person to person, but on average most people need 7 to 8 hours of sleep each night. Most adults do experience insomnia from time to time, but for some people the condition may be present for an extended period and is called chronic insomnia. Insomnia of a more temporary nature that occurs occasionally for just a few days at a time is called acute insomnia. At times, acute insomnia may simply develop as a symptom of some other health condition or a side effect to certain medications.