Amitriptyline is primarily used as an antidepressant to treat symptoms of depression. It works by balancing certain natural chemicals in the brain, which helps improve mood and feelings of well-being. Beyond its use for depression, it is also prescribed for managing chronic pain conditions, such as neuropathic pain, migraines, and fibromyalgia. Additionally, it is sometimes used off-label to treat insomnia, anxiety disorders, and certain eating disorders. Due to its sedative effects, it is often taken at night to help with sleep disturbances associated with depression or other conditions. Always follow medical advice for its use, as it requires careful monitoring for side effects and interactions.