PCP (phencyclidine) is classified as a hallucinogen and has many of the same effects as LSD, but can be much more dangerous. In the 1950's, PCP was investigated as an anesthetic, but due to it's severe side effects, it's development for human use was discontinued. PCP is known for inducing violent behavior and and for inducing negative physical reactions such as seizures, coma, death.
http://www.google.ca/search?q=cache:QHgcOjINq9QJ:www.streetd...

The Mental Status Examination is the most important area of abnormality in PCP intoxication. A great deal of variability frequently occurs in the mental status findings with these patients, and, at times, their results may appear normal or nearly so, while a few (20 or so) minutes later, obvious psychosis and possible evidence of dangerousness to self and/or others will appear. Therefore, one must document the hallucinations, delusions, and mood-related issues (such as suicidal and homicidal thinking) carefully and with reference to the time of the examination because changes may occur.
http://www.emedicine.com/med/topic3118.htm