Effects of Modafinil, Caffeine and Methylphenidate in Healthy Volunteers

In this study the investigators compare three stimulants to each other. The effects of these agents on cognitive performance (eg, attention and memory) and on the brain are being measured. The hypothesis is that stimulants will have a positive effect on cognitive performance. Each study participant will receive once a placebo and once methylphenidate or modafinil or caffeine. Methylphenidate (also known as Ritalin ®) is a drug that is used in the treatment of attention deficit / hyperactivity disorder (ADHD) in children, adolescents and adults. Modafinil ( Vigil ®) is a drug used in the treatment of narcolepsy (sleeping sickness). In the study. These substances are given in the study only once and in the dosages in which is also used for the treatment of the above diseases. In the case of caffeine , the dosage corresponds to two cups of coffee.