The purpose of this study is to investigate effects of methylphenidate, modafinil, and 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy") on emotion-processing and cognitive performance using functional magnetic resonance imaging (fMRI) techniques. The primary hypothesis is that these psychostimulants differentially affect processing of emotional stimuli and potentially leading to alterations in social cognition and behavior.

Methylphenidate and modafinil are increasingly used as performance enhancers or "smart drugs" by students. 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy") is widely used as recreational drug to enhance emotions. We plan to investigate effects of these psychostimulants on emotion-processing and cognitive performance using functional magnetic resonance imaging (fMRI) techniques. Single doses of methylphenidate (60mg), modafinil (600mg), MDMA (125mg), or placebo will be administered before an fMRI scan in a placebo-controlled, randomized cross-over study design in 24 healthy subjects. Subjective emotional effects, sociability, neurohormonal, cardiovascular responses, and plasma drug concentrations will also be assessed and analyzed for potential brain-induced changes in brain activity in networks processing emotions. The primary hypothesis is that these psychostimulants differentially affect processing of emotional stimuli and potentially leading to alterations in social cognition and behavior. The work should clarify the neuropharmacological basis of the potentially differential effects of these drugs. This information will improve our understanding of the neurofunctional effects of methylphenidate, modafinil, and MDMA, and inform the ongoing debate surrounding brain doping with cognitive and mood enhancers.

Inclusion Criteria:

• Age between 18 and 45 years
• Sufficient understanding of the German language
• Subjects understand the procedures and the risks associated with the study
• Participants must be willing to adhere to the protocol and sign the consent form
• Participants must be willing to refrain from taking illicit psychoactive substances including cannabis during the study
• Participants must be willing to drink only alcohol-free liquids and no xanthine-containing liquids (such as coffee, black or green tea, red bull, chocolate) after midnight of the evening before the study session, as well as during the study day
• Participants must be willing not to drive a traffic vehicle within 24h following MDMA administration
• Women of childbearing potential must have a negative pregnancy test at the beginning of the study and must agree to use an effective form of birth control. Pregnancy tests are repeated before each study session.
• Body mass index: 18-27kg/m2

Exclusion Criteria:

• Chronic or acute medical condition including clinically relevant abnormality in physical exam, laboratory values, or ECG. In particular: Hypertension (>140/90mmgHg) or Hypotension (SBP<85mmHg). Personal or first-grade history of seizures. Cardiac or neurological disorder. This also includes contraindications for MRI scanning (any type of implants such as heart pacer, insulin-pump, cochlea-implants, heart valve)
• Current or previous psychotic or major affective disorder
• Psychotic or major affective disorder in first-degree relatives
• Prior illicit drug use (except tetrahydrocannabinol (THC)-containing products) more than 5 times or any time within the previous 2 months
• Pregnant or nursing women
• Participation in another clinical trial (currently or within the last 30days)
• Use of medications that are contraindicated or otherwise interfere with the effects of the study medications (monoamine oxidase inhibitors, antidepressants, sedatives etc. )
• Tobacco smoking (regularly > 10cigarettes / day)