It’s been almost one month since Fidji Simo announced she would not return to her role as the No. 2 exec at OpenAI because of the fragile state of her health. My colleague Emily Forlini, who covers AI for Fortune, just published the first interview with Simo since she left her position.

Simo told Emily that her health is “physically the worst [it’s] ever been.” But she is still working on an important project: her company ChronicleBio, which aims to find cures to complex conditions like POTS, which is what Simo has. These are often conditions that mostly affect women and that can leave patients completely disabled—sensitive to light and sound, spending most of their time in a completely dark room with no stimulation. But they don’t cause death, which is another reason research into these diseases doesn’t get funded.

The company is trying to solve a specific problem in clinical trials, which is that diseases like POTS often have “sub-diseases,” with different underlying genetic causes contributing to the same set of symptoms. A drug could work well for one sub-disease, but not most patients, and right now the trial would likely be canceled. As Emily explains, ChronicleBio is “finding patients with similar symptoms, grouping them together, and then testing drugs on those subgroups so the trial is more likely to be successful.”