We are proposing a randomized, double-blind, crossover study. A total of 40 male and or female subject completers will have two 4-day treatment periods, in which they will be randomized to minocycline (200 mg/day) or placebo. During the first 3 days of each treatment period, subjects will have daily clinic visits for medication administration and monitoring of adverse events. On Day 4, subjects will have an experimental session in which measures of mood and cognitive performance will be obtained. Following a washout period, ranging from 5 to 15 days, subjects will be crossed over to the alternative treatment.