Trauma only appearing in super-deep going therapy sessions can often be False Memory Syndrome, which is an entirely different can of worms and extremely problematic. If you search really really deeply, you're going to find it, wether it exists or not.

Generally: While suppressed memory of trauma exists, the vast majority of people are aware of trauma and there is no evidence suggesting otherwise. And there is clear evidence that lots of mentally well people get addicted as well, so just claiming "it's always some underlying condition" is probably not a great idea. It can, often even, be, sure. But that doesn't make it mandatory and especially doesn't allow the "I struggle with addiction, so there _must_ have been a problem beforehand" conclusion.

So honestly, I'd just not search any deeper to not risk inducing any false memories.