Meditation is supposed to bring one close to the spiritual world, but people forget that besides beings of light, beings of darkness ALSO live in the spiritual realm...
I think if you pull out the history book and review 1600s America and Europe....especially the witchcraft trials...you see all the elements of this maximized mediation and mindfullness (mania, depression, hallucinations and psychosis). This study goes a long way in explaining the mental state of the witchcraft-players and how people got caught up in the whole mania at the time.