If you have trouble falling or staying asleep, or you wake up feeling unrefreshed, you may be suffering from insomnia. Insomnia is a symptom. It may be caused by stress, anxiety, depression, disease, pain, medications, sleep disorders or poor sleep habits. Your sleep environment and health habits may also play a role in your sleep problems.Some medications can lead to insomnia as well. These include medications for cold and allergy (some antihistamines and decongestants, high blood pressure (antihypertensives), heart disease (betablockers), thyroid disease and birth control (hormones), as well as asthma and pain medications (containing caffeine).