Smoking Cessation Study In Healthy Adolescent Smokers

• Drug: Varenicline 1mg BID
  
  Oral Varenicline 1mg BID, or 1/2 that dose (0.5mg BID) for those subjects that weigh less than or equal to 55kg at baseline, for twelve weeks, follow-up through Week 52
• Drug: Varenicline 0.5mg BID
  
  Oral Varenicline 0.5mg BID, or 1/2 that dose (0.5 QD) for those subjects that weigh less than or equal to 55kg at baseline, for twelve weeks, follow-up through Week 52
• Drug: Placebo
  
  Oral placebo for twelve weeks,follow-up through Week 52

• Experimental: Varenicline 1mg BID
  
  Oral Varenicline 1mg BID, or 1/2 that dose (0.5mg BID) for those subjects that weigh less than or equal to 55kg at baseline, for twelve weeks, follow-up through Week 52
  Intervention: Drug: Varenicline 1mg BID
• Experimental: Varenicline 0.5mg BID
  
  Oral Varenicline 0.5mg BID, or 1/2 that dose (0.5 QD) for those subjects that weigh less than or equal to 55kg at baseline, for twelve weeks, follow-up through Week 52
  Intervention: Drug: Varenicline 0.5mg BID
• Placebo Comparator: Placebo
  
  Oral placebo for twelve weeks,follow-up through Week 52
  Intervention: Drug: Placebo

Inclusion Criteria:

• Healthy male and female subjects between the ages of 12 and 19, inclusive.
• Subjects smoking at least an average of 5 cigarettes per day, motivated to stop smoking,
• Subjects must have at least one prior failed attempt to quit smoking.

Exclusion Criteria:

• Subjects with history, current diagnosis, or treatment of major depression disorder, anxiety disorders, panic disorder, hostility or aggression disorder, perceptual/thinking disturbances, mania, psychosis, bipolar disorder, personality disorder, eating disorder or severe emotional problems (in the past year).
• Subjects with a prior suicide attempt: subjects hospitalized within the past 12 months due to suicidal ideation or suicidal behavior; subjects considered to have serious suicidal ideation or suicidal behavior in the past 12 months; active suicidal ideation or behavior identified at the screening or baseline visit.
• Evidence of alcohol and substance abuse/dependence (other than nicotine) within 3 months prior to screening.