not a regular user of e-cigarettes
pregnant or lactating (only excluded from imaging study)
prisoner
incapable of giving informed consent
unable to lie flat on the scanner for extended periods of time
unstable medical condition like heart disease, uncontrolled hypertension, thyroid disease, diabetes, renal or liver impairment, or glaucoma
prostatic hypertrophy, stroke, or ulcer in past year
psychiatric conditions such as schizophrenia, adult ADHD, or bipolar disorder
current or regular use of psychiatric medications such as tranquilizers, antipsychotics, and/or antidepressants
use of medications that are inducers of CYP2A6 (a nicotine metabolizing enzyme) such as rifampicin, dexamethasone, phenobarbital, and other anti-convulsant drugs
unable to communicate in English
current use of smokeless tobacco, tobacco cigarettes (5 and fewer a day)
occasional use of pipes is permitted if subject abstains for the week prior to the study
older than 80 years

NCT03491059_exc_T1
Person
regular user
NCT03491059_exc_T2
Procedure
e-cigarettes
NCT03491059_exc_T3
Negation
not
NCT03491059_exc_T5
Person
prisoner
NCT03491059_exc_T8
Qualifier
unstable
NCT03491059_exc_T9
Condition
medical condition
NCT03491059_exc_T10
Condition
heart disease
NCT03491059_exc_T11
Condition
hypertension
NCT03491059_exc_T12
Qualifier
uncontrolled
NCT03491059_exc_T13
Condition
thyroid disease
NCT03491059_exc_T14
Condition
diabetes
NCT03491059_exc_T15
Condition
liver impairment
NCT03491059_exc_T16
Condition
 or  rment, or
NCT03491059_exc_T17
Condition
glaucoma
NCT03491059_exc_T18
Scope
heart disease, uncontrolled hypertension, thyroid disease, diabetes, renal or liver impairment, or glaucom
NCT03491059_exc_T19
Condition
prostatic hypertrophy
NCT03491059_exc_T20
Condition
stroke
NCT03491059_exc_T21
Condition
ulcer
NCT03491059_exc_T22
Condition
psychiatric conditions
NCT03491059_exc_T23
Condition
schizophrenia
NCT03491059_exc_T24
Condition
adult ADHD
NCT03491059_exc_T25
Condition
bipolar disorder
NCT03491059_exc_T26
Scope
schizophrenia, adult ADHD, or bipolar disorder
NCT03491059_exc_T27
Drug
psychiatric medications
NCT03491059_exc_T28
Drug
tranquilizers
NCT03491059_exc_T29
Drug
antipsychotics
NCT03491059_exc_T30
Drug
antidepressants
NCT03491059_exc_T31
Scope
tranquilizers, antipsychotics, and/or antidepressants
NCT03491059_exc_T32
Drug
medications
NCT03491059_exc_T33
Qualifier
inducers of CYP2A6
NCT03491059_exc_T34
Drug
nicotine metabolizing enzyme
NCT03491059_exc_T35
Drug
rifampicin
NCT03491059_exc_T36
Drug
dexamethasone
NCT03491059_exc_T37
Drug
phenobarbital
NCT03491059_exc_T38
Drug
anti-convulsant drugs
NCT03491059_exc_T39
Scope
rifampicin, dexamethasone, phenobarbital, and other anti-convulsant drugs
NCT03491059_exc_T41
Procedure
smokeless tobacco
NCT03491059_exc_T42
Procedure
tobacco cigarettes
NCT03491059_exc_T43
Multiplier
5 and fewer a day
NCT03491059_exc_T44
Scope
smokeless tobacco, tobacco cigarettes
NCT03491059_exc_T46
Person
years
NCT03491059_exc_T47
Value
older than 80