Comment by ncasenmare

Hi, author of the blog post here! Thanks for bringing this up -- it wasn't my intention to say one should replace antidepressants with vitamins (the conclusion even says "(Don't quit your existing antidepressants if they're net-positive for you!)", but you're right that the intro may give that impression. I'll edit the intro to say you can stack, not substitute, regular antidepressants.

> many studies in the Vitamin D meta-analysis enrolled patients already taking antidepressants.

Yes, and that's even more encouraging, that there's still effects of Vitamin D on major depression even if already on antidepressants! This suggests we can "stack" the interventions.

Table 1 of the meta-analysis ( https://pmc.ncbi.nlm.nih.gov/articles/PMC11650176/ ) shows the raw sub-group analysis. There were 9 studies on patients using antidepressants, 13 on patients who weren't, the rest were Mixed or Not Reported (...how do 6 studies just not report that?) Anyway,

Effect size of Vit D for people on antidepressants: −0.54 (−0.85, −0.23)

Effect size of Vit D for people NOT on antidepressants: −0.28 (−0.40, −0.16)

Both negative. Weirdly, the effect of Vit D seems to be a bit stronger for people on antidepressants, but the difference isn't statistically significant at the p<0.05 level (P subgroup difference is 0.23)

(As for why those effect sizes, -0.54 & -0.28, are lower than what I (and that meta-analysis itself) report, -1.82, that's because the majority of RCTs for any group used far less than 5000 IU. Table 2 in that paper shows the effect (with 95% CI) for various dosages.)

I'll lightly edit my blog post to emphasize stack them, don't substitute. Thanks again for your comment!