I don't know how this compares to similar studies (if there are any similar studies) but microdosing is almost never done 3 weeks apart. That's usually the time frame done for macro dosing (but with multiple grams not mg).
Even the study at the top mentions that
>Reported microdoses identifed in observational research typically range from 5 to 20 μg of LSD and from 0.1 to 0.3 g of dried psilocybin mushrooms. Microdoses are most commonly used several times a week with various patterns of alternating days.
Are these doses small enough that you don't notice the immediate effects?
The above comment study is pretty interesting, points to equivalent effectiveness.
> On the basis of the change in depression scores on the QIDS-SR-16 at week 6, this trial did not show a significant difference in antidepressant effects between psilocybin and escitalopram in a selected group of patients. Secondary outcomes generally favored psilocybin over escitalopram, but the analyses of these outcomes lacked correction for multiple comparisons. Larger and longer trials are required to compare psilocybin with established antidepressants.
For no significant difference in outcome, I'd much rather have two psilocybin sessions versus daily SSRI use.
For lsd this is generally under 15~20ug, though 5ug/10ug is generally what people dose at.
These dosages aren't well established with "proper studies" but I can say that people documenting there experiences seem to establish this pretty well. The psychonauts wiki is a good place for this type of information