A mood diary is a tool used in CBT to help individuals track their emotions and the situations that trigger them. By recording their mood fluctuations, thoughts, and behaviors throughout the day, individuals can identify patterns that contribute to their emotional well-being or distress. Mood diaries are especially helpful for managing conditions like depression, anxiety, and bipolar disorder. By keeping a detailed record of their emotional experiences, individuals can work with their therapist to address the specific triggers and develop strategies for managing negative moods and improving emotional regulation.