That is a common misconception that can become true if a person fails to do other things in addition to enemas such as eating right, exercising the colon with fiber and cleansing the liver to increase bile flow. :) You know how people are, they tend to do just one thing, one magic bullet, and then blame it when things don't go their way! ;)
Enemas are not at all addictive or dependency forming in any way. They will clean you out so well that you don't need to go for a day, as it usually takes at least 6 hours for food to pass through the 10 feet or so of intestine. sometimes that gets mistaken for constipation.
Healing the bowels is a systemic process, cover all the bases and make enemas just one part of your protocal and you'll be fine.