This captures a facet of depression that I think is portrayed in a fairly neat way. I could go one way or the other on "a parasite that forces depression on you", but I think that aspect is written well.
I don't feel scared or horrified by this. I have clinical depression as well, and it's pretty shitty and awful, but I never felt that this is reflective of that. By forcing it through the lens of scientific curiosity and categorization, it gets drenched in clinicality to where it's no longer something that feels real or something that hits home. I think this is further compounded by framing the story of depression between two people I can't care about by the end of the article. And if I were to read about people I don't care about, it'd be more interesting to see this spread among multitudes of people and see how they react to it, and how the parasite adapts.
Aside from this, I think the framing of Dr. Lawrence's notes mirrors SCP-2136 in a way that, while surely unintentional, doesn't feel as well-executed (and dragged on even longer). The listpages module trick didn't grab me here as well. The actual SCP portion of things is fine; it's everything else that I don't feel moved by in any single way, let alone scared by.