The purpose of this study is to investigate the safety and tolerability of AZD2066 using multiple escalating dose panels. There will be separate panels for young healthy volunteers and elderly healthy volunteers. Each panel will contain 10 volunteers who will randomly receive AZD2066 or placebo. One panel will be run at a time with a fixed dose given. After the completion of each panel, a Safety Review Committee will decide if the study can proceed to the next dose panel.