In fiction, characters can hide their depression in a variety of ways, often depending on their personality and background. Common ways of hiding depression include: 1. **Pretending to be happy**: Characters may try to act upbeat and cheerful, using smiles and humor to mask their inner pain. 2. **Social withdrawal**: They may gradually reduce their interactions with friends and family and try to avoid social situations. 3. **Loss of interest**: Characters may lose interest in activities they used to love and feel bored with life. 4. **Emotional outbursts**: Although they try to hide their emotions, they may occasionally lose control of their emotions over small things. 5. **Work or study obsession**: Characters use work or study to distract themselves from facing their emotions. 6. **Substance abuse**: Some characters may begin to abuse alcohol or drugs to numb their emotions. As for extreme behavior, characters may express their inner struggles in the following ways: 1. **Self-harm**: Such as cutting their wrists or hitting themselves to distract themselves from the mental pain of physical pain. 2. **Impulsive behavior**: Such as reckless driving or risky activities, which may show indifference to death or injury. 3. Extreme life changes: quitting a job, moving, or ending a relationship in an attempt to completely change one’s life. 4. Desperate actions: writing goodbye letters or engaging in self-harming behaviors that seek attention from others. These actions not only drive the plot forward in fiction, but they often reveal the depth and complexity of the character’s heart. By carefully describing these actions, the author can help the reader better understand the character’s inner world.