Marijuana

Originally posted by Chruser Frequent inhalation of cannabis smoke over a period of years can lead to bronchitis and other respiratory disorders, cancer of the lung and other parts of the digestive tract.

This is the fact that most people use cigarette to inhale cannabis.
Oh btw, do you know that some asthma trouble are cured with canabis sativae as medecine ? true !

Very high doses can also cause coma in young people,

Cafein cause the same trouble in very high doses

not to mention it may also exacerbate existing mental health problems.

Cannabis is use as a medecine in certain phsychatric treatment.
For a non 'exacerbate EXISTING mental health problem', there no way to worry about.

I pity those of you who say that it's a harmless drug.

I pity those who say that chocolat is a harmless drug

Alcohol can be addictive unlike the mentioned drug, and yes, it usually has more harmful effects if you consume it a lot,

100% agree.
just one thing, Alcohol is addictive, ok, but cannabis has a certain psychological dependence. 'Certain', because it may vary from one subject to the other.

but on the other hand, small controlled consumptions of alcohol are safer than small consumptions of "weed".

50% agree with you. It's not safer, it's just as harmfull.(didn't wanted to say that's it is the opposite.... )
BTW, mixing alcohol and 'weed' is not advised.