Generalized anxiety disorder (GAD) is characterized by excessive, uncontrollable worry that interferes with daily life. While the exact causes are unknown, genetics and abnormal brain chemistry may play a role. Common symptoms include restlessness, difficulty concentrating, muscle tension, and feeling easily startled. Approximately 9 million Americans have GAD, with about half experiencing symptoms their entire life. Treatment options include medications and cognitive behavioral therapy, with the latter being the most effective approach through techniques like monitoring worries and facing fears.