A new report has found that teenagers are at risk of permanently damaging their brains by smoking marijuana.
Drugs are one of the biggest dangers facing young people and we invited an expert into the Newsround offices to answer your questions.
Petra Maxwell from drugs information charity DrugScope was online on Friday. Here's what she had to say.
Dreamz: The statistics are all wrong - it says 1 in 10 smoke cannabis. I0t's 1 in 10 admit to surveys - 4 in 10 actually smoke dope.
Petra: The latest statistics from the government showed that around 11% of 11-15 yr olds say they have smoked cannabis, which is around one in ten.
These surveys always include test questions to make sure the answers are as truthful as possible, so they are pretty accurate. So that means that if you are not smoking cannabis you are in the huge majority!
Fantapple: Hi Petra - I'm 14 and I smoke cannabis probably about once a month with my friends, I've been doing it for about a year, we share about 2/3 spliffs. It has done no damage so far it is not regular and I can live without it? Am I gonna get any damage?
Petra: Most of the research so far suggests that you are most at risk if you are smoking cannabis on a very regular basis, ie two or three times a week.
However, as we saw on Newsround earlier, it is also more risky the younger you are when you start using the drug, so if you are smoking cannabis when you are 14, there is going to be a risk there as well.
Also, even the experts don't really know yet what the long-term effects of smoking cannabis from an early age are.
ruben-philip-billie-joe: Smoking is harmful to the lungs and drinking is harmful to the liver. They're still legal. Why is cannabis different?
Petra: Well neither of them are legal for young people, but I know what you mean. To be honest, some of it is historical, because both tobacco and alcohol have been used for such a long time in this country.
It has been said that if they were introduced now as new drugs they would also be illegal. In some other countries in the world, alcohol is illegal.
Smoking cannabis is also harmful for your lungs in a similar same way that cigarettes are, but it also has these mental health risks attached to its use.
Highplace: Why do we only hear the bad possible effects about the drug and never the good?
Petra: You're right: research has also found that some of the ingredients in cannabis can be used in medicine, in particular to help people who suffer with multiple sclerosis and arthritis.
There are medical companies at the moment who are trying to find a way to use these ingredients to help people without having any of the negative side effects that smoking cannabis can have, and they expect to have a product in the next year or two.
¿ßê©kÿ: Has anyone ever taken cannabis before? I did last Saturday. I think it might have been mixed with other drugs. I had hallucinations! Scared me really badly - I advise anyone not to use it!
Petra: Lots of people who try cannabis find that they don't like the experience at all. As Becky says, some stronger types can even make you have hallucinations, which can be frightening at the time.