 Because the results of the double-blind placebo-controlled and open-label glycine treatment arms showed substantial clinical benefit to the participants, the study has been extended to include six months of chronic open-label glycine in order to determine 1 whether the clinical benefits achieved within 6 weeks previously recur, 2 the clinical benefits are lasting, and 3 additional clinical benefits occur with longer exposure. The glycine for this extension will be provided by Letco Medical. 