Vitamin D as a Therapeutic Adjunct in the Stimulant Treatment of ADHD

Specific Aim 1: As part of a within-subject, two-days, study design, to determine whether acute calcitriol (vs. placebo) pre-treatment is associated with greater amphetamine (Amp)-induced dopamine (DA) release in the caudate, putamen, ventral striatum (VST), and substantia nigra / ventral tegmental area (SN/VTA) of healthy human subjects. Specific Aim 2: To determine whether acute calcitriol (vs. placebo) pre-treatment is associated with better performance on a test of attention (e.g., the Continuous Performance Task or CPT-IP), after treatment with amphetamine. Hypothesis: Investigators hypothesize that Subjects pre-treated with calcitriol will have faster reaction times/higher accuracy on the CPT-IP vs. subjects pre-treated with placebo, after treatment with amphetamine.