do you think depression can only be “caused” by something?

when i got diagnosed with depression and started seeing a therapist, our sessions kind of only consisted of trying to find out what trauma in my past was the root of my depression. but i feel like the way i feel doesn’t have a reason, i’ve honestly haven’t really lived through anything terrible or traumatic, but still my therapist thought that i just wasn’t sharing something in my past that was the reason for why i have depression today.

i stopped going to a therapist at all because i was tired of feeling like sessions weren’t doing anything, she didn’t believe me when i said that there wasn’t a trauma to blame..