The association of amygdala-insula functional connectivity and adolescent e-cigarette use via sleep problems and depressive symptoms

BACKGROUND

Adolescent electronic cigarette (e-cigarette) use remains high. Elucidating contributing factors may enhance prevention strategies. Neurobiologically, amygdala-insula resting-state functional connectivity (rsFC) has been linked with aspects of sleep, affect, and substance use (SU). As such, we hypothesized that amygdala's rsFC with the insula would be associated with e-cigarette use via sleep problems and/or depression levels.

METHODS

An adolescent sample (N = 146) completed a rs-fMRI scan at time 1 and self-reports at time 2 (∼15 months later). Given consistent associations between mental health outcomes and the rsFC of the laterobasal amygdala (lbAMY) with the anterior insula, we utilized a seed region (lbAMY) to region of interest (ROI) analysis approach to characterize brain-behavior relationships. Two serial mediation models tested the interrelations between amygdala's rsFC with distinct anterior insula subregions (i.e., ventral insula [vI], dorsal insula [dI]), sleep problems, depression levels, and days of e-cigarette use.

RESULTS

An indirect effect was observed when considering the lbAMY's rsFC with the vI. Greater rsFC predicted more sleep problems, more sleep problems were linked with greater depressive symptoms, and greater depressive symptoms were associated with more e-cigarette use (indirect effect = 0.08, CI [0.01,0.21]). Indicative of a neurobiological dissociation, a similar indirect effect linking these variables was not observed when considering the lbAMY's rsFC with the dI (indirect effect = 0.03, CI [-0.001,0.10]).

CONCLUSIONS

These outcomes highlight functional interactions between the amygdala and insula as a neurobiological contributor to sleep problems, depressive symptoms, and ultimately SU thereby suggesting potential intervention points to reduce teen e-cigarette use.

Electronic Cigarette Use Intentions Mediate the Association between Low Self-Control and Future Use by Internalizing Symptoms

Background: Adolescent electronic (e-)cigarette use intentions are related to initiation. Low self-control is also a risk factor for early stages of substance use. Yet, the impact of low self-control on use through intentions may vary across individuals; depression and anxiety may affect this association. Methods: A sample of 200 adolescents who completed waves 1 and 2 of an ongoing longitudinal study were assessed. We hypothesized that high internalizing symptoms would moderate the indirect effect of low self-control on actual e-cigarette use through e-cigarette use intentions. Results: The mediation pathway was significant at high levels of internalizing symptoms, but not at low or moderate levels. Conclusion: Specifically, those with low self-control and high internalizing symptomatology endorsed the highest e-cigarette use intentions and were more likely to subsequently use e-cigarettes. Youth low in self-control and high in depression and anxiety might be at increased risk to initiate e-cigarette use compared to youth high in self-control and high in internalizing symptomatology.

Alexithymia mediates the association between childhood trauma and adolescent E-cigarette use

BACKGROUND

Adolescent electronic cigarette use (e-cigarette) is a public health concern and factors associated with vaping remain to be understood. Childhood emotional abuse/neglect is a risk factor for e-cigarettes. Yet, pathways by which trauma impacts use remain unclear. Alexithymia (i.e., difficulties identifying and describing feelings) is one possible link. Indeed, emotional abuse/neglect leads to difficulties identifying and verbalizing emotions. This impairment may lead to distress and promote e-cigarette use as a coping strategy.

METHODS

Using parallel mediation, this study examined the degree to which alexithymia, assessed using the Toronto Alexithymia Scale, mediates the link between emotional abuse/neglect, assessed using the Child and Adolescent Trauma Screen, and e-cigarette use. The sample (n = 166) consisted of adolescents from a larger multi-wave study.

RESULTS

Emotional abuse/neglect predicted difficulty describing feelings (effect = 0.23, p = 0.001), which in turn predicted e-cigarette use (effect = 0.30, p = 0.004). Moreover, difficulty describing feelings mediated the link between emotional abuse/neglect and e-cigarette use (sum of indirect 95% CI [1.68, 16.48]). Difficulty identifying feelings was not a significant mediator and the externally-oriented thinking subscale was excluded due to low reliability.

CONCLUSIONS

As e-cigarettes are often used in social contexts, teens who experience difficulty describing feelings may vape as a means of connecting emotionally with others. Moreover, nicotine, found in most e-cigarettes, releases dopamine and noradrenaline in the brain modulating action, learning, and memory processes; plausibly, improving verbalization of emotions. Programming which identifies nuances in alexithymia among adolescents with emotional abuse/neglect could mitigate e-cigarette use or delay initiation.