Causes

Repeated exposure to jet lag, stress, caffeine, tobacco and other situations that cause sleep disturbance can lead to chronic insomnia. However, chronic insomnia is generally caused by more complicated factors such as physical and mental illness. One of the most common causes of chronic insomnia is depression.

• Illnesses such as lung, heart, or kidney disease, Parkinson's disease
• Hyperthyroidism
• Another sleep disorder such as sleep apnea, narcolepsy, restless legs syndrome
• Pain, anxiety, and depression
• Medicines that have side effects that cause sleep disturbance Decongestants, Beta blockers, Antidepressants, Alcohol, Bronchodilators, Pain medicine with caffeine, Stimulants such as Ritalin, Corticosteroids; and Thyroid hormone replacement.
• Smoking before going to bed
• Poor sleep environment, i.e. noisy, too hot or cold, uncomfortable
• Change in sleep routine
• Side effects of a medication such as those taken for colds and allergies, high blood pressure, heart disease, thyroid disease, birth control, asthma, pain and depression, especially SSRI antidepressants.
• Change in the sleep environment (hotel, camping)
• Stress
• Jet lag
• Blindness-inability to detect light and darkness can disrupt the biological clock
• Night shift work