Here is a definition I have stolen (borrowed)from Wikipedia.com (http://en.wikipedia.org/wiki/Psychosis)
Psychosis: (from the Greek ψυχή "psyche", for mind or soul, and -ωσις "-osis", for abnormal condition), with adjective psychotic, literally means abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality". People suffering from psychosis are said to be psychotic.
People create a layered web of illusions and delusions around themselves. Categorizing themselves and others, romanticizing and amplifying scenarios, situations, forecasts of the future and interpretations of the past to build a world around themselves that they can be comfortable with.
Reality is defined by the individual observing reality; the person who interprets their surroundings. This allows each of us to create our own reality within ourselves. This is psychosis.
Since it is common among most humans, you can't exactly call it "abnormal" but it is a "loss of contact with reality" in the sense that each of us view our realities individually and can't agree upon a common interpretation.
It would be great to clear away the cobwebs and see ourselves and the world around us, as we truly are. Frightening maybe, but refreshing nonetheless.
Strip away the self-induced filters and we can stop finding justification for our guilt, anticipating the reactions to our actions and make ourselves right with ourselves.
I know this is a rant and maybe hard to follow but I can't stop questioning my own reality. I see examples of people pushing others away because they challenge their reality. We reject those that do not fit into the story that we are writing. Every day is a casting call on the set of your life and you are approving and denying people entry into your reality. We are human beings and sometimes we are in opposition to ourselves. Each of us have the potential to be extremely cruel and callous one minute and then trustworthy, caring and generous another. We live our lives along that spectrum trying to define ourselves within our world. When we question our reality, we are questioning "who we are".
Who are we and why are we here?
Are we all the same identical soul, cast into varying circumstances, reacting to our world and changing based on our scenario? Are we ONE soul, recast over and over again into the same timeline as different people? Are we all fragments of ONE consciousness; traveling through creation trying to jigsaw ourselves back into a whole?
I don't know the answers, I just can't stop asking the questions.