In a book I’m planning on writing, one of the characters has depression. What are the most common symptoms, and is it possible for him to do things that help with it (other than meds or therapy)? I’m not saying it would cure him but it would help him cope with it. Is that possible? If it is, what kinds of stuff would help him? Is it possible for him to be depressed without a tragic backstory or a history of trauma? I wasn’t planning on giving him either but if I have to I will.
Don't try to compensate for ignorance by guessing what it's like. Depression is likely ubiquitous in modernity, to various degrees of severity, so it'd just come across as offensive.
Have you played through a round of depression quest? I wouldn't call it perfectly accurate, but it does convey some of the nuances in a clever manner.
"I wasn't planning on giving him [a history of trauma] but if I have to I will."
You remind me of this post I'd once seen: "...So tadashi is this perfect role model / model citizen type guy? - Right! - Sooo what do we do with such a character? The audience will get bored with him. - ... KILL HIM."