How can you be sure that your research results will not be used by others in wrong ways beside medical purposes? If you are really sure that your research will never be used but only in medical purposes, then it will be allowed to do such research, but if you have any possibility that others can misuse your research even in future or by illegal ways, then you must avoid such work because it is not allowed to put any effort to support wrong whether directly or indirectly, now or in the future.
No it is not allowed. Even if it is considered in some countries as
legal, that does not make any difference because it is an intoxicant
and every intoxicant is Haraam (forbidden) in Islam and the change of the laws will not change our religion. Many countries consider alcohol as allowed
although Islam has forbidden it. We abide by the rules of Islam
wherever we live. ‘There is no cure in any intoxicant’ as the Hadith
from Imam Ja’far As Sadiq (AS) states.
Smoking weed or any intoxicant material is not allowed in Islam. There is no exception in such matters. Harmful is harmful, hence it can never be allowed even if you think that you might get relief , as no real relief can be achieved through such harmful things at all.
It is not allowed to consume any intoxicant.