It really is not a habit, just as dermatillomania is not a habit, this is very much like saying that something like OCD is just a habit.

There is a genuine compulsion, and impulse behind these disorders, I suffered from skin picking (dermatillomania) for years ( and I did not limit myself to skin alone ). When I would engage in these behaviors I would be in a trance like state. This trance like state allowed me to feel a calm rush over me when nothing else could. I would spend hours and hours straight in the bathroom picking and unable to stop or leave and do something else. I would have rituals that would surround my experience. This interfered with my life a great deal. There is a reason why "mania" is part of the name, if you look it up in this term, meaning madness, or a nicer way to put it than the Etymology site that was from is ..an irrational but irresistible motive for a belief or action. Not mania as in Bipolar.

My friend has suffered with trichotillomania since she was five, she is now nearly 30 and still cannot overcome this disorder, she pulls her hair, eyelashes and brows, and any other hair that is available on her body. It's not easy for her to "answer" when people question why she has no brows or lashes, she is quit self conscious about it, if she could just stop, and stay stopped that easily she would.

There is not a ton of treatment for these disorders where we live, and frankly they go unrecognized and fall by the way side.