Intervention: Varenicline
Trial phase: Phase 4
ATC code: N07BA03 | S01XA28
SMILES: c1cnc2cc3c(cc2n1)C1CNCC3C1
Sex: All
Age groups: Adult
Healthy volunteers: No
Participants at risk: 2
Group description: Varenicline (Chantix) : Upon completion of screening procedures and meeting eligibility criteria, subjects will begin taking varenicline daily until Week 6 of the study. At Week 6 they will discontinue varenicline and return one week later for their final study visit to assess return of ADHD symptomatology. Subjects will start on 0.5 mg of varenicline per day for the first week of treatment. The dose will be increased to 0.5 mg twice a day at the end of week 1 visit, and then increased to 1 mg twice a day at the end of week 2 visit, to remain at this dose until the week 6 visit. At week 6, all subjects will be openly discontinued from varenicline, to return to the office the following week for re-assessment one week off the medication. If significant adverse effects (AE) occur, the daily dose may be reduced by 0.5 to 1 mg. At subsequent visits, a higher dose may be resumed if
Eligibility criteria:
Inclusion Criteria:

Male and female outpatients from 18-60 years of age;
A cigarette smoking history of at least 3 months, and currently smoking;
An interest in quitting smoking and a willingness to comply with all study procedures and medication instructions;
A current DSM-IV-TR diagnosis of ADHD confirmed by clinical psychiatric evaluation and/or ADHD module of structured diagnostic interview, completed by study clinician.
For females of child-bearing potential: pregnancy test at screening visit is negative and the subject does not plan to become pregnant during the study.

Exclusion Criteria:

Pregnancy or breast-feeding;
Clinically significant and/or unstable medical condition including renal, hepatic, or neurological, based upon a medical history and vital signs;
Ongoing treatment with medications which may be affected (altered blood levels) if subjects stop smoking in the study, including insulin, theophylline, and blood thinners, as determined by clinician;
Clinically significant cardiovascular history, including myocardial infarction, untreated hypertension, atrial fibrillation, or arrhythmia;
Current untreated psychiatric comorbidity which the investigator judges to be of greater than mild severity, including Major Depressive Disorder;
Current psychiatric comorbidity, including suicidality, homicidality, psychosis, determined by the clinician to be clinically significant and/or unstable
Lifetime history of DSM-IV Bipolar I disorder, Schizophrenia, or suicide attempt as determined through clinical evaluation or diagnostic interview;
Currently (within 3 months) meets DSM-IV criteria for abuse or dependence for any psychoactive substance other than nicotine;
Current treatment with mood stabilizers, anti-psychotics, nicotine replacement therapies, or varenicline;
Mental retardation (IQ < 75);
History of intolerance or allergy to varenicline.

Clinically significant abnormal screening values including:

Consistent readings of hypertension (>140/90) during screening period (including screening and baseline visits), defined as two or more readings (each being the average of three measurements) at a single visit with systolic blood pressure, SBP > 140 and/or diastolic blood pressure, DBP, > 90, and confirmed by manual reading.

Subjects with isolated incidences (of triplicate average BP) of SBP > 140 and/or DBP > 90 at baseline/week 0 visit, confirmed by manual reading, which are determined to be clinically significant.