Caffeine use is on the rise in America, and one of the most popular sources is soda. Among youth ages 8-16, caffeine consumption has increased by over 70% in the past 30 years. Few studies have examined the role of hormones in caffeine consumption within this age group.

The purpose of the current experiment was to determine the effect of caffeine on children 8 and 9 compared to those 15 and 16 years of age. The investigators were looking at the effect of puberty on the consumption of caffeine as well as the effect that the caffeine has on the body (for example: heart rate, blood pressure) and cognitive function.

Our previous studies have demonstrated sex differences in both the reinforcing properties of (Temple JL, Briatico LN, Clark EN, Dewey AM, 2009) and physiological responses to (Temple JL, Dewey AM, Briatico LN, 2010) caffeine. This is consistent with the literature on other types of drugs showing that men and women often differ in both drug self administration (Lynch WJ,2008 ) and drug sensitivity (Temple, JL, et al, 2008). These differences have been attributed, at least in part, to differences in gonadal hormones (Lynch WJ, 2008) ,Dreher JC et al, 2007). Our laboratory conducted a study investigating subjective effects of caffeine in post-pubertal adolescents and found that boys reported greater drug effects and liking of drug effects than did females (Temple JL, Dewey AM, Briatico LN, 2010, Temple JL, Ziegler AM,2011). In addition, the differences in feeling of the drug effects were related to salivary estradiol levels in females, but not in males, suggesting that steroid hormones can mediate the subjective effects of caffeine. When taken together, these data suggest that there are gender differences in acute and chronic effects of caffeine and that these differences may be mediated by differences in circulating steroid hormones. Previous studies have shown that subjective responses to caffeine vary across the menstrual cycle (Terner JM, de Wit H, 2006), with the greatest subjective effects occurring during the follicular phase, when estradiol levels begin to rise and peak just prior to the ovulatory LH surge. To date, no well-controlled studies have been conducted in humans examining the relationship between steroid hormones and caffeine effects on cognition, which the investigators will address in this study.

Inclusion Criteria:

• males and females from 8-9 yoa or 15-17 yoa (post pubertal)
• those 8-9 much have Tanner Staging below 3
• those 15-17 much have Tanner Staging above 3.
• willing to come into the lab 6 times for 1.5-2 hours each
• those willing to abstain from consuming caffeine for 24 hours before each appointment
• those willing to withdraw from consuming anything other than water for 2 hours before each appointment.
• 15-17 year old females much have begun menarche

Exclusion Criteria:

• those on ADHD medication or other's impacting caffeine metabolism
• those reporting being on birth control or other hormones
• those that are pregnant or breastfeeding
• those outside the given age range or pubertal classification
• those reporting having an adverse effect of caffeine in the past

all participants had all treatments across all studies on this project

We collected adverse events over the five year period covered by this funding proposal.