Insomnia is a symptom of several sleep disorders, characterized by difficulty falling asleep, referred as sleeplessness. Insomnia may be due to the inadequate quantity of sleep. Insomnia is not defined by how long it takes to fall asleep. Individuals vary normally in their need for, and their satisfaction with sleep. Insomnia can lead to severe fatigue, anxiety, depression and lack of concentration. Insomnia is serious, although unlike other diseases it does not kill. It occurs more often in women than in men, and symptoms are common as people age. A probable 30% -50% of the general populations are affected by insomnia.

Types: Insomnia may be primary or secondary:

• Primary insomnia - the inability to sleep is not caused by other health problems.

• Secondary insomnia - is due to other health conditions that interfere with sleep.