Two of the major medications for smoking cessation are full agonist nicotine replacement therapies (nicotine gum, patch, inhaler, lozenge/microtab and nasal spray) and the partial nicotine agonist varenicline. Since full agonist nicotine replacement therapy (West & Shiffman 2001) and partial agonist therapy (Fagerstrom & Hughes 2007) both reduce nicotine withdrawal including depression, this should reduce the amount of suicide initially after cessation. On the other hand, since these medications are nicotine agents and the same argument stated above -that (a) nicotine is a psychological toxin or (b) since nicotine is an antidepressant, it might cause suicide (see above) -might apply. One could hypothesize that since varenicline is a partial agonist, its antidepressant effects should be less than with full agonists and, thus, any suicide risk from being an antidepressant should be less. On the other hand, varenicline does have antagonist effects, and nicotine antagonists appear to have antidepressant actions and thus might have potential to induce suicide (Rabenstein et al. 2006).
