With respect to the effect: You can use as well as misuse alcohol, and you can use as well as misuse cannabis.

Sean:
Please.  Who do you think you're talking to here??  Can I use and misuse crack too??

Struthio:
What about opium?

Fr. Doran quotes the first part of Jone, where he says that using small amounts occasionally constitutes venial sins ... without sufficient reason, but then conveniently leaves out the second part, where it states that the small amounts can be used occasionally without sin for relatively light reasons, like calming the nerves.

With regard to marijuana, that "microdosing" thing reportedly gives you the good benefits such as relief of anxiety, lifting of spirits, etc. ... without impairing reason or judgment.  I don't see how that would be a sin at all ... assuming that it's legal where you're at and doesn't put your job at risk.  Recall that the chief reason why it can be sinful is due to the impairment of reason, so if that's taken off the table, I'm not seeing the principle whereby it would be inherently sinful.

As Fr. Scott wrote it up, even taking one hit off a joint so that it doesn't impair reason would constitute a mortal sin ... unless used for medical reasons. Nothing about his explanation makes sense except for the part that everyone agrees on, where it's a grave sin to use it to the extent of significantly impairing the use of reason ... absent a grave circuмstance such as severe pain, etc.

I mean, Fr. Scott discredits his narrative right out of the gate by claiming that "The old text books [on moral theology] do not speak of this new problem of the modern world."  Really, drugs didn't exist until the modern world?  They've been around since the beginning of recorded history.  And the theology books did in fact deal with it.  Did he even bother to casually leaf through a couple of them?  We already have references to Jone and Merkelbach, and I bet lots of moral theologians discussed the issue.  Again, drugs are NOT NEW.

Then this is also a false statement:  "All the other effects, such as relaxation, come as a consequence of this “high,” or unreal euphoria."  This is demonstrably false.  Relaxation can be achieved with SMALL doses long before there's a high.  This "high" comes about from dosing higher.  If anything it's the opposite, that the "high" comes from extending the effects to large doses, from "excess relaxation".  I see absolutely zero reason to distinguish the use of a small amount of marijuana from a relatively small amount of alcohol, where it gets you to relax and lifts your spirits.  Sacred Scripture speaks of wine that it "brings joy to the hear of man." (Psalm 103).  So is this joy the consequence of the "high"?  No, the only difference between alcohol and marijuana is the legality.  It's increasingly becoming legal and the legality of alcohol vs. the illegality of marijuana is completely arbitrary, and historically it was engineered by Rockefeller for his oil interests.