Adolescent Caffeine Consumption,Daytime Sleepiness,and Anger

Abstract

Introduction:

Caffeine use has been increasing among adolescents and young adults but much remains to be known about the consequences and context of their use.

Methods:

With self-reported anger as the key outcome variable, 7348 Icelandic adolescents were surveyed for caffeine consumption, cigarette smoking, alcohol use, daytime sleepiness, and potential confounders. Structural equation modeling was used to examine direct and indirect effects of seven latent constructs: parental education, parental support, peer support, caffeine consumption, licit substance use (nicotine and alcohol), sleepiness, and anger; and two direct effects were measured using variables for family structure and family financial status.

Results:

Daily caffeine consumption was reported by 76.3% of participants, and of the four caffeine beverages surveyed, cola drinks were most often consumed, followed by energy drinks, tea, and coffee. Boys reported more caffeine use on average than girls, with the difference being particularly marked for consumption of cola and energy drinks. Girls reported significantly more sleepiness and more anger symptoms overall than boys, but there were no gender differences on the measures of cigarette smoking and alcohol consumption. Amount of caffeine consumed was strongly associated with other substance use (nicotine and alcohol) and strongly associated with daytime sleepiness. Structural equation modeling showed that a substantial proportion (43% for girls and 48% for boys) of the total relationship between caffeine and anger was due to mediation through sleepiness and licit substance use.

Conclusion:

High prevalence of daily caffeine consumption and the strength of the observed associations between caffeine and other important biobehavioral and psychosocial variables demonstrate the importance of including measurements of caffeine consumption in future studies of adolescent adjustment and development.