The goal of this application is to test whether menthol and fruit flavors impact e-cigarette use through dissociable mechanisms and exert their effects differentially across nicotine doses.
This study examines the impact of menthol and fruit flavors on self-administration of e-cigarette solutions containing varying amounts of nicotine. This is a randomized, double-blind study with a within-subject cross-over design, using e-liquids with 5 different flavors and 4 different levels of nicotine for a total of 20 different e-liquid formulations. Each subject will participate in 4 test sessions. The order of flavor and nicotine delivery will be randomized. At each test session, they will undergo directed self-administration, in a randomized order, then an ad libitum self-administration session where they can choose among all of the e-cigarettes used during the directed session. The primary aims assess the impacts of nicotine and flavor (and their interactions) on participants' subjective ratings of the e-liquids during the 'directed' self-administration component, and self-administered puffs during the ad libitum self-administration component. In addition, the study will explore the impact of sex/gender and sensitivity to nicotine aversiveness or bitterness (as operationalized by genetic variations in the alpha-5 subunit of nicotinic acetylcholine receptor that influences the aversive effects of nicotine, or a taste receptor number 38 ( TAS2R38) important for bitterness perception) on study outcomes.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
DOUBLE
Enrollment
54
E-liquid containing no nicotine (0 mg/mL nicotine) will be self-administered via e-cigarettes. This will be administered in 5 flavor conditions (1 unflavored, 2 menthol, and 2 fruit conditions).
E-liquid containing low nicotine (6 mg/mL nicotine) will be self-administered via e-cigarettes. This will be administered in 5 flavor conditions (1 unflavored, 2 menthol, and 2 fruit conditions).
E-liquid containing medium nicotine ( 12 mg/mL nicotine) will be self-administered via e-cigarettes. This will be administered in 5 flavor conditions (1 unflavored, 2 menthol, and 2 fruit conditions).
Yale University School of Medicine
New Haven, Connecticut, United States
Subjective drug ratings
Subjective ratings of e-liquids delivered via e-cigarette will be assessed during the 'directed' self-administration component of each test day, using visual analogue scales (VAS). VAS scores range from 0=not at all to 100=extremely. Separate VAS scales will be collected for subjective ratings of aversive properties (higher scores reflect more aversiveness) and rewarding properties (higher scores reflect more rewarding properties) of the e-cigarettes, in each nicotine\*flavor condition. Subjective drug ratings for each nicotine\*flavor condition will be tested at one test day only and the order of nicotine\*flavor conditions will be randomized across the test days (and order within test days will be randomized).
Time frame: immediately after intervention
E-cigarette use
Number of puffs from each e-cigarette (containing different e-liquids) will be measured during the ad libitum self-administration component of each test day. E-cigarette use (ad libitum puffs) for each nicotine\*flavor condition will be tested at one test day only and the order of nicotine\*flavor conditions will be randomized across the test days (and order within test days will be randomized).
Time frame: immediately after intervention
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.
E-liquid containing high nicotine ( 24 mg/mL nicotine) will be self-administered via e-cigarettes. This will be administered in 5 flavor conditions (1 unflavored, 2 menthol, and 2 fruit conditions).
E-liquid containing 'menthol' flavor will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
E-liquid containing 'menthol/mint' flavor will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
E-liquid containing 'green apple' flavor will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
E-liquid containing 'watermelon' flavor will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
E-liquid containing no additional flavor (i.e., 'unflavored') will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).