I've worked at an IT company as a consultant for a little more than a year and I currently work at a customer's office who's really happy with me.
My boss put me forward for an in-house training, which is held by fellow employees for us. I've been there four times so far and it's been absolutely terrible every time. The two people running the training (Seniors) have no idea how to teach, or behave like decent human beings.
It appears as if the two Seniors expected us all to already know everything before even attending - on top of ongoing harassment and condescending behavior towards us. (e.g. "What do you even do at work all day?")
To go more into detail: We're attending a Java Backend training, but I for example don't work in Backend development (I'm a Jr. in test automation); some of us don't even code in Java. Yet we're expected to be on the same step of training from the beginning. Many, including me, are left behind.
Currently, we forwarded our concerns about the quality of the training, but I heard from a friend who also works there that the same two employees made everyone attend a test to see what they've learned so far and threatened that bad results would "affect your next appraisal interview" after they didn't get the results they wanted. This is not the change I've been rooting for.
I've been diagnosed with chronic depression years back but I'm doing fine on the job otherwise. Every week at which I've got an appointment for this training my productivity suffers all week, because I start doubting myself. I fear this will throw me back on the long run and yield no results on top of it.
My question is: How could I approach my boss about this and that it damages my mental health?
UPDATE: I phoned up my boss and told him I don't feel well about the training and that it doesn't help me with my current career path. He dismissed my concerns, because he's convinced we're being taught Java basics, which is not the case. His assumption here is based on his personal perception of basics, which does not correlate well with us. He told me to go to the next appointment tomorrow and then give more feedback. Overall the conversation wasn't very fruitful.
So far I am unsure of how to keep arguing my point. I'll hold out for the next training and then update again.
UPDATE2: The next training mentioned above was much better. As opposed to before the Seniors actually cared to ask things like "Did you do this before in a project?" and also consulted us for our opinions a lot more often. We were able to discuss answers and not just get a "I am right and you're wrong and that's a fact". Their approach has turned a lot more humble overall and they're eager to learn how they can do better.
I told my boss as much that the interpersonal aspect has gotten much better and as such I was able to follow the training better, too. Things did stay civil and I am really happy it played out like this for the time being.