I have intentionally flown into clouds a few times to experience the effects. As you know even experienced pilots can lose orientation in a cloud... so much so that even up and down can confuse them.
I never experienced that degree of disorientation... but it definitely can effect recognizing a turn-bank-decent etc. I can well imagine that in a situation where you suddenly find yourself in a cloud, not having any intention of doing so, it would be more difficult than how I did it... with full intent.
