The Food and Drug Administration on Wednesday announced it has ordered the makers of the prescription anti-smoking medications Zyban and Chantix (also known by their pharmaceutical names bupropion and varenicline) to warn patients that taking the drugs may cause changes in behavior and mood, including hostility, agitation, depression and suicidal thoughts or behavior...

Both medications were approved by the FDA after their manufacturers presented evidence that taking these drugs increased a smoker's likelihood of successfully quitting the habit.