Since it's not possible to be physically addicted to cannabis, your question is ridiculous.
Japan doesn't have a drug problem? Hehehehehehehehe. Define "drug problem".
What are cancer rates in Japan like, since Fukushima? Worse than ever. Maybe that's because they don't have access to cannabis, which cures most cancers?
If you say stupid shit on this page, you're going to get an earful of knowledge, just letting you know for next time. ;)