I agree cloudsurfer: What’s the use of a defence mechanism? Against what? Freud saw the unconscious as a much more dangerous place than it is. The unconscious doesn’t have ‘dangerous’ thoughts. Not to the thinker.
I don’t think there is surpresssion at all, Freudian, spiritual or otherwise. I think it’s much simpeler: The brain doesn’t question reality. It just doesn’t. Not in waking life, not in dreams. Sure, on a summers evening with a bottle of wine we may steer it in that direction and thus become more aware, which in a dream might make us lucid. But we hardly ever do that.
Now in our dreams our brain does more or less the same as it does in waking state, except now it doesn’t have any input except our own thoughts and fantasies. Why should it all of a sudden start questioning our perception now? And when something weird happens it does what it always does: come up with an explanation, just as in waking life.
And through eons of evolution and through our entire lives, the brain has never had a need to question reality. So this LD fad is basically about developing a skill that has been totally uncalled for throughout human life. So I don’t think it’s active surpression, but rather a lack of developement. Which doesn’t mean we can’t develop it, it just takes a lot of resourcefulness.