I know PTree is busy with stuff right now...but she's the expert on psyllium and I know that she'd say that your bowels wouldn't become addicted to the psyllium. The psyllium isn't a laxative, it is just fiber (think of it like...is your body addicted to carrots and salads? good fiber that is good for you?)....and psyllium promotes HEALTHY peristalsis (colon muscle movement that pushes the stool through) unlike herbal laxatives which simply irritates the lining and doesnt' promote healthy peristalsis.
Nothing to worry about, the pysllium is good for you!