4. Cannot abstain from using stimulants such as amphetamines (e.g., Adderall, Ritalin, etc.); caffeine (e.g., coffee, cola, etc.); ephedrine (e.g., diet pills, energy drinks, etc.); and eugeroics (e.g., Modafinil, Provigil, etc.) from at least 9:00 AM on Visits 2 and 3