I wouldn't know the effect of clutter clearing because I am a hoarder and live in squalor.
I even sunk to the depths of humiliation of being on a hoarding show but the "organizer" was not all that helpful except to help discard obvious trash and clean things. There was no real help for actual organizing of my possessions and I cannot locate many items that the "organizer" stashed into boxes/closets for out of sight, out of mind but that hasn't helped my house to be more functional.