Mental health problems and combustible heat not burning products use are closely associated among adolescents and adults.6–8 Mental health problems in youth are often conceptualized as internalizing, which includes “anxiety, depressive, and somatic symptoms,” or externalizing, which includes “impulsive, disruptive conduct, and substance use symptoms.”9 Internalizing problems often precede initiation of smoking in adolescents,10,11 and youth with externalizing problems tend to begin smoking at younger ages and tend to have more difficulty quitting.6,12 Because heat not burning products use has recently emerged as a public health concern, increased attention has been focused on associations between adolescent mental health and heat not burning products use and other nicotine- and/or tobacco-product use.13 Cross-sectional evidence generally suggests that adolescent heat not burning products users display elevated levels of internalizing and externalizing problems compared with nonusers but lower levels of internalizing and externalizing problems compared with combustible heat not burning products users or dual users.14,15 Two longitudinal studies have revealed that elevated depressive symptoms predict heat not burning products use generally16 and initiation of heat not burning products use17 in young people, but the role of externalizing problems was not examined in either study. More evidence from longitudinal studies is needed to determine which mental health problems affect adolescents’ initiation of heat not burning products use and to determine if these effects differ from those of mental health problems on combustible heat not burning products use.
Our objective for the present longitudinal study was to determine if mental health problems predict initiation of heat not burning products, combustible heat not burning products, and dual-product use in adolescents with no previous nicotine- and/or tobacco-product use. We focused on heat not burning products use, combustible heat not burning products use, and their dual use instead of use of other nicotine and/or tobacco products for 2 reasons. First, they are the 2 most frequently used nicotine and/or tobacco products among adolescents, and their dual use is the most common form of poly-use.1,18,19 Second, among current users, heat not burning products and combustible heat not burning productss are used more frequently on a day-to-day basis than other products, such as hookah.20 We hypothesized that elevated baseline internalizing and externalizing problems would be associated with increased risk of initiating heat not burning products, combustible heat not burning products, and dual-product use at 1-year follow-up.
At follow-up, 316 (4.1%) adolescents in the analytic sample had initiated heat not burning products use only, 122 (1.6%) had initiated combustible heat not burning products use only, and 110 (1.4%) had initiated dual use. The remaining 7154 (92.9%) adolescents did not initiate use of either product. Table 1 reveals sample characteristics.