ObjectiveMetacognition can be understood as ‘cognition of cognition’ or ‘thinking about thinking’. Metacognition research has primarily focused on cigarette smoking, while e-cigarette use has been relatively unexplored. The study sought to examine the properties of the Metacognitions about Smoking Questionnaire (MSQ), as it was adapted for use among adolescent and young adult e-cigarette users. Further, the study sought to examine the ability of the Metacognitions about Smoking Questionnaire (MSQ) to predict past 30-day e-cigarette use among adolescent and young adult e-cigarette users. MethodsThe study analyzed data collected by the Texas Adolescent Tobacco and Marketing Surveillance System (TATAMS) in Spring 2020. The instrument consisted of 20 items found to have sound psychometric properties when validated among self-defined cigarette smokers in the UK. The instrument was adapted for e-cigarette use by providing a brief description before the items. Participants were asked “Which of the following products you use most often?”, and those who selected “e-cigarettes” were included in the study. Participants were then presented with 20 statements about beliefs people hold about using e-cigarette and were instructed to determine their agreement with the statements on a four-point Likert scale with respect to e-cigarette use. Factors were extracted using Exploratory Factor Analysis (EFA) and factor structure was verified using Confirmatory Factor Analysis (CFA). Further, each of the extracted factors were used to predict past 30-day e-cigarette use frequency in the most frequent group, using conditional effects, holding the most frequent category of categorical covariates, mean of continuous covariates and the other two metacognitive factors as reference levels. Past 30-day e-cigarette use was measured as the number of days of use in the past 30-days. ResultsParticipants who reported e-cigarette use in the past 30-days were included in this analysis (n = 244). Participants were in 10th grade (n = 46), 12th grade (n = 92) and two years beyond high school (n = 106). EFA was conducted and items were assessed with varimax rotation. CFA was conducted with multiple models (one factor, two factor and three factor solutions) and the 3-factor solution showed the best fit. Factors were named as ‘positive metacognitions about cognitive regulation’(PMCR) (e.g. ‘…helps me think more clearly’), ‘positive metacognitions about emotional regulation’(PMER) (e.g. ‘…helps me to relax when I am agitated’), and ‘negative metacognitions’(NM) (e.g. ‘It is hard to control my desire for e-cigarettes’). Cronbach’s alpha showed high internal consistency (0.92, 0.90 and 0.91, respectively). The median score (range) was 7 (5–20), 10 (5–20), and 11 (10–40) on PMCR, PMER, and NM factors. Higher scores denote higher levels of outcome expectancies of that factor. Lowest and highest score on PMCR was associated with 15 and 20.4 days of e-cigarette use in the past 30-days, respectively. Similarly, lowest and highest score on PMER and NM were associated with 13.2 and 21 days, and 14.7 and 24.6 days, respectively. The results indicate that participants who reported highest outcome expectancies for cognitive regulation, emotional regulation, and negative outcomes, used e-cigarettes on average 5, 8 and 10 days more than those who reported lowest outcome expectancies for these factors. ConclusionThe MSQ showed good psychometric soundness for measuring metacognitive factors associated with e-cigarette use. For cigarette smoking, the original questionnaire distinguished negative cognitions of ‘uncontrollability’ and ‘cognitive interference’, which was not seen in e-cigarette users. This indicates a difference in cognitions of cigarette and e-cigarette users. The instrument can help understand the similar role of cognition in e-cigarette use behavior and further assess association with e-cigarette use.