Insomnia is defined as the inability to fall asleep or stay asleep. Common symptoms include difficulty falling asleep, waking up during the night, and waking up early in the morning. Insomnia can be caused by physical health conditions like heart disease or respiratory illnesses, as well as stress, anxiety, and mood disorders. Prescription medications and substances like caffeine can also cause insomnia. Treatments include cognitive behavioral therapy to change unhelpful sleep habits, sleeping pills in severe or short-term cases, and melatonin which is a natural hormone that helps regulate sleep cycles.