Effects of Caffeine on Sleep-wake Regulation in Teenagers

Caffeine-induced Effects on Sleep, Cognitive Performance, and Underlying Cerebral Correlates During Adolescence - a Randomised, Placebo-controlled, Double-blind Clinical Study

The aim is to quantify the effects of one dose of caffeine (compared to placebo) on sleep and wakefulness in adolescents.

Inclusion Criteria:

• Self-reported habitual caffeine consumption: min. 80 mg per month until max 300 mg per week as estimated from mean caffeine content per serving of caffeine containing beverages and food
• Body-Mass-Index: 16.2-25.4
• Informed Consent as documented by signature of participant
• Informed Consent as documented by signature of legal representative

Exclusion Criteria:

• Previous enrollment into the current study
• Investigators' family members, employees or other dependent persons
• Left-handedness
• No normal current health as based on questionnaires, screenings of urine, and examination by the physician in charge
• Drug use: Volunteers must be drug-free for the entire duration of the study, with no history of drug or alcohol dependency.
• Participation in other clinical trials <3 months prior to study begin
• Shift work <3 months prior to study begin
• Transmeridian travel (>2 time zones) <1 month prior to study begin
• Extreme Chronotype (Munich Chronotype Questionnaire [17], MCTQ <2 or >7)
• Short or long sleep duration: subjective sleep duration during schooldays not between 6-10 h (based on MCTQ)
• Inability to follow procedures
• Insufficient knowledge of project language (German)
• Circumstances endangering MRI safety
• Non-compliance with sleep/wake times during ambulatory part (deviation of more than ±1.5 hour from scheduled times)