Mold is being remediated in my house as I type this. My wife and I have been dealing with insidious symptoms for years (brain fog, joint pain, anxiety, muscle stiffness, balance issues, neuropathy, increased ADHD, and more). Only recently did we discover that there was black mold (Stachybotrys chartarum) in both our bedroom and in the air supply trunk located after the air handler. The bedroom mold was caused by an inactive leak that must have been there before we ever bought the house. The air handler was due to poor installation alongside high humidity.
We’ve already noticed a huge decrease in symptoms about 10 days after the air handler was pulled.