Marijuana - Harmful Effects Marijuana can cause many harmful effects. There has never been a major test though. The ones they’ve used have shown very different things. I have been very surprised by what I have been reading. I cannot believe the difference in what different scientists think. One says, “It's hard to know for sure whether regular marijuana use causes cancer. But it is known that marijuana contains some of the same and …showed first 75 words of 2418 total…

…showed last 75 words of 2418 total…in adapting to intellectual and interpersonal tasks, he says.” Well I don’t know which ones to believe. They all have done lots of research as well as I. I think that most likely NIDA is right because it is run by the government. The government may be trying to make it sound worse then it is though. No matter what though marijuana is a very harmful drugs. It should not be used by anyone.