To qualify, participants must meet the following criteria (Additional Criteria Apply):
* Be a man or woman between the ages of 18-60
* Have not used an experimental drug or medical device within one month
* Must be otherwise healthy based on a physical examination and medical history
* Be a current, recreational, not physically dependent user of sedative/depressants at least 10 times in their lifetime and once within the past year
* Not be a heavy smoker