I'd like to see some controlled studies with marijuana.
Cannabis is on Schedule 1. Which, IIRC means zero beneficial medical use (think heroin, cocaine).
See the recent article with pictures of the "marijuana" that the government gives to researchers.
And with Sessions as the AG, I don't think the situation is changing soon.
Depression is probably a bad fit for Cannabis. Within the space of drugs that are used recreationally, Ketamine is (was?) the big hope.