[robbedpeter]

That's implied with the "responsible" framing. Part of that means knowing your mental health situation, if you have family history of schizophrenia or other risk factors, or if your doctor recommends against it.

Another part is self-education. Have conversations, explore the intellectuals and history and science of the subject, and learn your mental health situation. If psychedelics are inappropriate, or if you're uncertain, then the responsible thing to do is to simply avoid them.

At any rate, it looks like microdosing, to our best understanding, lacks evidence of benefit when considered against the possibility of placebo. We also know that the potential for heart damage from microdosing recommends against it. Lastly, we know for a fact that responsible full dose trips are among the most positive and powerful experiences available for people. I'd call that "definite," within the constraints of responsible use.