- Healthy male subjects 21 - 45 years old.
- Able to read and write English as primary language.
- Subjects who are willing to comply with study procedures.
- History of any substance abuse or dependence disorder meeting DSM-IV criteria and/or
by SCID-NP within the past 12 months, with the exception of nicotine.
- Known sensitivity to ketamine
- Any history of DSM-IV Axis I psychiatric disorders, determined by SCID-NP interview
or diagnoses in the view of the investigator.