There are many signs of depression in cats, such as:
1. Cats may exhibit lethargy, drowsiness, or over-excitement, and lose interest in their usual favorite toys or games.
2. Depressed cats may experience decreased appetite or overeating, leading to significant weight changes.

3. Cats may defecate or urinate in places where they shouldn't, or they may urinate and defecate frequently, which could be due to emotional stress.
4. A cat's fur may become rough, fall out, or develop skin inflammation, which is generally related to its psychological state.