Please select the eligibility criteria that correspond to the clinical trial below.
Title: Efficacy of Varenicline in Ambivalent Smokers
Brief Summary: The purpose of this study is to test whether Varenicline can help ambivalent smokers (those who are interested in quitting at some point in the future but have no current plans to quit) to reduce their smoking and eventually quit.


Options:
A: Inclusion Criteria:

1. Age: 18-65 years old
2. Smoking: \>/= 5 cigarettes per day within the 2 months preceding the screening visit and expired CO greater than or equal to 6 ppm.
3. Able to follow verbal and written instructions in English and complete all aspects of the study
4. Have an address and home telephone number where they may be reached
5. Provide informed consent and agree to all assessments and study procedures
6. Be the only participant in their household

Exclusion Criteria:

1. Within the month immediately preceding the screening visit; use of any form of tobacco product other than cigarettes on 3 or more days within a week only if the individual refuses to refrain from non-cigarette tobacco use during the course of this study
2. Within the month immediately preceding the screening visit; use of marijuana in any form on 3 or more days within a week
3. Within the two weeks immediately preceding the screening visit, involvement on more than 3 days in any formal smoking cessation activities
4. Current visual or auditory problems that in the opinion of the investigator would interfere with the completion of study assessments
5. Treatment on a continuous basis within 2 weeks before the screening visit: any contraindicated medication for Varenicline or Bupropion.
6. Uncontrolled hypertension or other major contraindications for Bupropion or Varenicline.
7. Severe renal impairment (CR Clearance \<30 ml/min/1.73 m2).
8. Laboratory evaluations outside normal limits and of potential clinical significance in the opinion of the investigator
9. Meet current criteria for psychiatric disorders or substance abuse as assessed by the MINI for items A, B, D, I, J, K, L, M and N, including a past manic or hypomanic episode as well as a lifetime psychotic disorder.
10. Subject rated as moderate to high on suicidality as assessed by the MINI.
11. Psychiatric hospitalization within 1 year of screening date.
12. A positive urine pregnancy test during the screening period. Women who are two years post menopausal, one year post-tubal ligation, or who have had a partial or full hysterectomy will not be subject to a urine pregnancy test.
13. Pregnant, breast-feeding, or of childbearing potential who is not protected by a medically acceptable, effective method of birth control while enrolled in the study
14. Use of Varenicline or Bupropion within two weeks before the screening visit.
15. History of hypersensitivity or allergic reaction to Varenicline, tricyclic antidepressant, Bupropion (Wellbutrin, Zyban) or similar chemical classes or any component of these formulations.
16. Subject considered by the investigator as unsuitable candidate for receipt of an investigational drug, or unstable to be followed up throughout the entire duration of the study.
B: Inclusion Criteria:

* At least 18 years old
* Able to get to research lab in Burlington, Vermont or Omaha, Nebraska
* Daily smoker
* Smoke at least 8 cigarettes per day
* No reduction in smoking in last 30 days
* No intention to quit in the next 30 days
* Never used Varenicline before
* Not currently using smoking cessation medications or nicotine replacement therapy
* Willing to use Varenicline for at least 2 weeks
* Fluent in English

Exclusion Criteria:

* Cannot be currently pregnant or breastfeeding
* Kidney disease
* Frequent nausea
* On certain medications for asthma and/or depression
* Another household member in study
C: Inclusion Criteria:

* Meets DSM-IV criteria for schizophrenia or schizoaffective disorder
* Receiving a stable dose of antipsychotic medication for at least 1 month prior to study entry
* Smokes at least 10 cigarettes per day
* Wishes to stop smoking
* Attended last three scheduled clinic visits, prior to study entry

Exclusion Criteria:

* Significant medical or neurologic illness
* History of severe head injury with loss of consciousness
* Treated with monoamine oxidase inhibitors or carbamazepine in the 14 days prior to study entry
* Taking clozapine at doses greater than 500 mg/d without an anticonvulsant
* Currently undergoing an acute exacerbation of psychotic symptoms
* Current or history of bulimia or anorexia
* Current excessive water intake
* Recent history of mania
* Known allergy or hypersensitivity to bupropion
* Current substance abuse other than tobacco, nicotine replacement treatment, or smokeless tobacco
* Currently receiving treatment with bupropion
* Pregnant or breastfeeding
D: Inclusion Criteria:

* Smoker seeking treatment
* Aged 18 and over
* Consenting to take part
* Report little or no change in enjoyment of cigarettes and/or nausea

Exclusion Criteria:

* Pregnant or breastfeeding
* Have severe kidney disease
* Have severe heart problems
* Have a current psychiatric illness
* Are unable to fill in questionnaires in English
* Have an allergy to varenicline
* Are currently involved in another clinical trial

Answer: B