What is Insomnia? Insomnia is a common sleep disorder involving difficulty falling asleep, staying asleep, or waking too early. It can cause fatigue, poor concentration, mood changes, and impaired daytime functioning. Insomnia is multifactorial - medical, psychological, behavioural, and lifestyle factors often interact to create and maintain sleep problems over time.Common contributors include: stress, anxiety, depression, medical conditions, hormonal changes, poor sleep habi