Secondary Insomnia Secondary insomnia is the symptom or side effect of another problem. This type of insomnia often is a symptom of an emotional, neurological, or other medical or sleep disorder. Emotional disorders that can cause insomnia include depression, anxiety, and posttraumatic stress disorder. Alzheimers disease and Parkinsons disease are examples of neurological disorders that can cause insomnia. Many other disorders or factors also can cause insomnia, such as: Conditions that cause chronic (ongoing) pain, such as arthritis and headache disorders Conditions that make it hard to breathe, such as asthma and heart failure An overactive thyroid Gastrointestinal disorders, such as heartburn Stroke Sleep disorders, such as restless legs syndrome and sleep-related breathing problems Menopause and hot flashes Secondary insomnia also can be a side effect of some medicines. For example, certain asthma medicines, such as theophylline, and some allergy and cold medicines can cause insomnia. Beta blockers also can cause the condition. These medicines are used to treat heart conditions. Commonly used substances also can cause insomnia. Examples include caffeine and other stimulants, tobacco and other nicotine products, and alcohol and other sedatives. Primary Insomnia Primary insomnia isnt a symptom or side effect of another medical condition. It is its own distinct disorder, and its cause isnt well understood. Primary insomnia usually lasts for at least 1 month. Many life changes can trigger primary insomnia. It may be due to major or long-lasting stress or emotional upset. Travel or other factors, such as work schedules that disrupt your sleep routine, also may trigger primary insomnia. Even if these issues are resolved, the insomnia may not go away. Trouble sleeping can persist because of habits formed to deal with the lack of sleep. These habits might include taking naps, worrying about sleep, and going to bed early. Researchers continue to try to find out whether some people are born with an increased risk for primary insomnia. 
What causes Insomnia ?