THC Crossover Study

Inclusion Criteria: * Healthy on the basis of medical history and limited physical examination, as described below: Heart rate \< 105 beats per minute (BPM); Systolic Blood Pressure \< 160 and \> 90\*; Diastolic Blood Pressure \< 100 and \> 50\* \*Considered out of range if both machine and manual readings are above/below these thresholds. * Current regular user of cannabis who smokes cannabis as joint or blunt at least 3 times a week for past 3 months * History of cannabis vaporizer use or willingness to use the vaporizer in the study * Current tobacco cigarette use who smokes ≥ 5 cigarettes per day * Saliva cotinine ≥ 50 ng/ml * Test positive for D-9-tetrahydrocannabinol (THC) at screening and self-report of cannabis use Exclusion Criteria: * Unstable medical conditions: Heart disease; Uncontrolled hypertension; Thyroid disease (okay if controlled with medication); Diabetes; Hepatitis B or C or Liver disease; Glaucoma; Prostatic hypertrophy * Psychiatric conditions: Current or past schizophrenia, and/or current or past bipolar disorder; Adult onset attention deficit hyperactivity disorder (ADHD); Participants with current or past depression and/or anxiety disorders will be reviewed by the study physician and considered for inclusion; History of psychiatric hospitalizations are not exclusionary, but study participation will be determined as per study physician's approval * Concurrent regular use of smokeless tobacco or pipes \[occasional users of these products may…