its considered a type of speed (upper) and can be gotten on the street and its also put in some diet pills to give people the "lift" or energy they need to lose weight. Sounds like the person is ODing on it or is hooked and going through a type of withdrawal. the person needs to get into therapy / rehab for addiction and get off the stuff before he/she causes themselves to go into cardiac arrest from Over Dose and/or major withdrawal.