OpenAI CEO of AGI deployment Fidji Simo is taking several weeks of medical leave to seek treatment for postural tachycardia syndrome, also known as POTS. Greg Brockman will handle the product teams in her absence.

"As I shared when I joined, I had a relapse of my neuroimmune condition a few weeks before starting the job. It's been a bit of a rollercoaster since, and the last month has been particularly rough health-wise. For my entire time here, I've postponed medical tests and new therapies to stay completely focused on the job and not miss a single day of work," Simo said.

Simo joined OpenAI in August 2025 and took over many of the company's consumer-facing products, including ChatGPT, Codex, and Sora. Her previous title was CEO of applications. During her tenure, she shuttered the Sora app and told staff that the company needed to cut side projects and refocus on its core products.

An OpenAI spokesperson said: "We have a strong leadership team focused on our biggest priorities: advancing frontier research, growing our global user base of nearly 1 billion users, and powering enterprise use cases. We're well-positioned to keep executing with continuity and momentum."

Simo was diagnosed with postural tachycardia syndrome in 2019. Doctors initially misdiagnosed her, with one doctor attributing her health issues to being a "tired mom." She co-founded the Complex Disorders Alliance and the Metrodara Foundation, through which scientists are conducting research to find cures for disorders such as POTS.

POTS is a disorder that affects the autonomic nervous system, which regulates involuntary functions such as blood pressure, heart rate, and respiration. It can cause heart palpitations, lightheadedness, and fainting. People with the condition often have orthostatic intolerance, a set of symptoms that occur when a person stands up and are relieved by lying down, according to the National Institute of Neurological Disorders and Stroke.

The condition mostly affects people between 15 and 50 years old and is more common in women than in men. It commonly begins after pregnancy, major surgery, puberty, trauma, or a viral illness, according to the National Institutes of Health. Some people report an increase in episodes right before their menstrual periods. People with a family history of POTS have a higher risk of developing the disorder. The cause of POTS is not yet known to scientists, according to the National Institute of Neurological Disorders and Stroke.

Additional symptoms can include blurred vision or tunnel vision, weakness in the legs, chest pain, fatigue, sleep problems, digestive issues, shortness of breath, and difficulty concentrating. Over time, POTS symptoms can improve, but some symptoms may remain or persist long term. Doctors typically begin diagnosing the condition by reviewing a person's medical history and discussing their symptoms, and may also measure heart rate and blood pressure while observing the body's response to changes in position such as standing up quickly.