Psychiatrist: Breaking any habit is difficult, especially when it involves an addictive substance. People who break a habit are more likely to be motivated by immediate concerns than by long-term ones. Ttherefore, people who succeed in breaking their addiction to smoking cigarettes are more likely to be motivated by the social pressure against smoking -- which is an immediate concern -- than by health concerns, since __.
The statement 'most people who succeed in quitting smoking succeed only after several attempts' supports the conclusion of the psychiatrist's argument.