[maxander]

If done only ~3 times, and only considering outcomes that manifest within a day or so. On possible harms beyond that the study is silent.

[ncmncm]

...appears harmless.

That said: I know firsthand that people who are borderline schizophrenic can have a very bad, long-lasting outcome from a regular dose of LSD. I doubt a microdose would do them any good. I hope that in studies like this, they screen the participants carefully.