The following assessments will be performed to determine the safety of MPH Hydrochloride: vital signs (blood pressure and pulse); monitoring effects/symptoms (side effects checklist). Those who report or show heightened blood pressure or heart rate side effects from the test doss of MPH at the clinical screening visit, e.g., systolic blood pressure exceeding baseline reading by 20mmHg, diastolic blood pressure exceeding the baseline reading by 10mmHg, BP > 160/100, or resting pulse increased by 20 beats/minute from the baseline reading will be excluded from the study. Subjective side effects will be measured for 21 potential side effects (e.g., headache, nausea, nervousness, etc.) by having subjects rate the intensity of their symptoms using the following scale : 1 = none, 2 = mild, 3 = moderate, 4 = severe. A qualified registered nurse is present throughout the entire session. Furthermore, thorough emergency plans have been implemented in conjunction with the Children's Hospital of Eastern Ontario (e.g. code blue) and the University of Ottawa should a crisis arise. In addition, the research unit has been equipped with a complete first aid unit cart along with an automated external defibrillator in which all the employees have been trained to operate. All employees are also required to maintain a valid CPR-C.