Drawing on stress and life-course perspectives and using panel data from 1,286 south Florida young adults, we assess three critical questions regarding the role of marijuana in the "gateway hypothesis." First, does teen marijuana use independently (causally) affect subsequent use of more dangerous substances? Second, if so, does that effect apply to the abuse of other illicit substances, as def...

INTRODUCTION Given the proposed changes to nutrition labelling in Canada and the dearth of research examining comprehension and use of nutrition facts tables (NFts) by adolescents and young adults, our objective was to experimentally test the efficacy of modifications to NFts on young Canadians' ability to interpret, compare and mathematically manipulate nutrition information in NFts on prepack...

BACKGROUND Few studies examining the genetic architecture of cigarette smoking have focused on adolescents or examined developmental changes in additive genetic, shared environment, and unique environmental influences on liability to initiate cigarette smoking and quantity of cigarettes smoked. The aim of this study was to add to the literature on liability to initiate and use cigarettes during...

Little is known about the rate of concussions in adolescents with attention-deficit hyperactivity disorder (ADHD). We hypothesized that high school athletes with ADHD would report a greater history of concussion than students without ADHD. A total of 6529 adolescent and young adult student athletes, between the ages of 13 and 19 years (mean, 15.9; standard deviation, 1.3), completed a preseason...

Patterson (1956) established that the age of Earth is close to that of meteorites. Over the last 20 years, workers argued for younger age for core differentiation based on Pb-Pb model ages and tungsten isotopic data and for gas retention based on I-Xe modeling. However, disagreement is abundant, and the young age of Earth has not been widely accepted. In this work, I examine all radiogenic nobl...