Certainly. Here is a study which shows that the use of marijuana may actually GROW brain cells
bioedonline.org/news/news.cfm?art=2083
And why marijuana is neither an intoxicant, nor a narcotic:
Narcotic, coined by the Greek physician Galen to refer to agents that benumb or deaden, causing loss of feeling or paralysis. It is based on the Greek word ναρκωσις (narcosis)
Use of the word “narcotic” to refer to any illegal or unlawfully possessed drug marijuana is common worldwide, although this is inaccurate because it is not considered to have narcotic effects in a medical context.
Intoxicant: the physiological state produced by a poison or other toxic substance typically resulting in inebriation.
Alcohol, opium/heroin and many other drugs are both numbing and toxic but cannabis is neither.
Cannabis does not block any neurotransmission nor does it produce the typical toxic side effects (withdrawal, nausea, hangover, overdose, death) of other drugs listed as either a narcotic or intoxicant.