Symptoms of insomnia can be caused by:
1. Environmental factors, e.g., noise
2. Disturbances of the circadian rhythm, such as shift work and jet lag, can cause an inability to sleep at some times of the day and excessive sleepiness at other times of the day. Chronic circadian rhythm disorders are characterized by similar symptoms.
3. Life events, such as fear, stress, anxiety, emotional or mental tension, work problems, financial stress, birth of a child and bereavement.
4. Hormone shift, such as those that precede menstruation and those during menopause.
(1). Restless legs syndrome, which can cause sleep onset insomnia due to discomforting sensations felt and the need to move the legs or other body parts to relieve these sensations.
(2). Periodic limb movement disorder, which occurs during sleep and can cause arousals that the sleeper is unaware of.
(3). Pain. An injury or condition that causes pain can preclude an individual from finding a comfortable position in which to fall asleep, and can in addition cause awakening.
(4). Parasomnias, which include such disruptive sleep events as nightmares, sleepwalking, night terrors, violent behavior while sleeping, and REM behavior disorder, in which the physical body moves in response to events within dreams.
(5). Medical disorders, such as hyperthroidism and rheumatoid arthritis.
(6). Neurological disorders, like brain lession, or a history of traumatic brain injury.
(7). Mental disorders, such as bipolar disorder, clinical depression, generalized anxiety disorder, post traumatic stress disorder, schizophrenia, obsessive complusive disorder, Dementia or excessive alcohol intake.
(1). Certain psychoactive drugs or stimulants, including certain medications, herbs, caffeine, cocaine, amphetamines, methylphenidate, MDMA and modafinil.
(2). Fluoroquinolone antibiotic drugs
(3). Abuse of over-the counter or prescription sleep aids can produce rebound insomnia.
7. A rare genetic condition can cause a prion-based, permanent and eventually fetal form of insomnia called fetal familial insomnia.