Marijuana smoke will cause cancer just like tobacco smoke or leaf smoke or Captain Crunch smoke will cause cancer. But the drug itself will not. Since marijuana mess with your brain chemistry, you will be a little hazy the day after. It does kill brain cells but it would take a whole week of heavy smoking to equal one night of binge drinking. And it is not physically addictive (although since the experience is so pleasant, many people can become mentally addicted to it.)