Insomnia is not considered a disease, as are some sleeping disorders, but it does affect 25% of the population occasionally, 10% as a chronic problem, and is the most common sleeping disorder of them all. Everyone experiences sleepless nights occasionally for various reasons, but chronic insomnia means that the brain is not getting enough rest, on a consistent basis, which can lead to greater problems.
Insomnia includes any combination of difficulty with falling asleep, staying asleep, intermittent wakefulness, and early-morning awakening. Some things that can cause or contribute to insomnia include illness, depression, anxiety, stress, poor sleeping environment, caffeine, abuse, alcoholism, heavy smoking, physical discomfort, daytime napping, certain medical conditions, and other sleeping habits like going to bed early, and excessive time spent awake in bed.
Consistent insomnia can result in reduced energy level, irritability, disorientation, dark circles under the eyes, posture changes and fatigue.