Pretty much, yes. The unconscious comprises of some 90-95% of the total of our consciousness and it's responsible for pretty much most of how we perceive both our internal and external realities. For instance, what you see isn't what you see, what your eyes actually see is a projection onto the inside of the sphere of your eyeball. The brain flattens the image, divides in into three parts and each part is processed by different parts of the brain at different speeds. Then it's all stitched back together again and you see in 3D. Similarly with all of your senses, it's the processing of information and what you become conscious of is the 'end result'.

Dreams are the unconscious mind communicating with the conscious mind, and often they are the unconscious trying to make the conscious mind aware of something. In that respect dreams can be dis-ease because the unconscious may be trying to make the conscious mind aware of an issue. So your dream of a soaring bird could be your unconscious trying to tell you that you feel trapped and you need to 'fly free'. Something similar can happen with mental health issues in that things like deamons are representations or personifications of mental health issues. So no, those of "sound mind" never see demons because they don't have mental health issues that need to be addressed.

It's when we see demons and hear voices (I do too) that people with mental health issues actually become more aware of perceptual reality than "normal people". They become more conscious of their unconscious and believe it or not, become more self-aware than "normal people".