To determine the safety of the selegiline concurrent with d-methamphetamine challenges of 15mg & 30mg i.v. with the focus being on cardiovascular responses (HR,BP) to the i.v. methamphetamine challenges. This is a randomized, single-blind, placebo-controlled, two-arm study design to evaluate the safety of selegiline treatment, compared to placebo treatment, concurrent with i.v. methamphetamine challenges.