"Zambon et al also found that having a good relationship with a best friend was related to increased use of cannabis, alcohol, and tobacco. Similarly, Hoel et al39 reported that although abstainers are successful in many social arenas, they socialize less frequently with friends than youth who drink, while a Finnish study40 indicated that moderate use of alcohol among adolescents was associated with a positive self-image in social relationships. Another
study,41 performed in New Zealand, also indicated an association between a high level of connectedness to friends and an increased level of smoking and use of cannabis in the previous month.
"In addition, and contrary to previous research,23 our study does not confirm the negative effect of cannabis on academic performance among COG youth. In our case, they are more likely to be high school students and they report similar grades as abstainers, even though they skip class more often."

Source

Suris, J. C.; Akre, Christina; Berchtold, Andre´; Jeannin, Andre´; Michaud, Pierre-Andre´, "Some Go Without a Cigarette: Characteristics of Cannabis Users Who Have Never Smoked Tobacco," Archives of Pediatric Adolescent Medicine (Chicago, IL: American Medical Association, November 2007) Vol. 161, No. 11, p. 1046.
http://archpedi.jamanetwork.c…