Fidji Simo is leaving her full-time position as OpenAI’s CEO of AGI Deployment after a prolonged health struggle involving postural orthostatic tachycardia syndrome, or POTS. She will remain connected to the company as a part-time adviser while focusing on recovery and neuroimmune research.
Fidji Simo steps back from OpenAI leadership
Simo announced on July 9 that she would step down from her daily executive responsibilities following a medical leave that began about three months earlier. She said the recovery from a severe flare-up had proved more complicated and time-consuming than expected.
OpenAI CEO Sam Altman recruited Simo in 2025 to oversee major product and business functions. Her role was initially called CEO of Applications and was later renamed CEO of AGI Deployment. She reported directly to Altman and managed teams covering products, engineering, operations and commercial strategy. She will now serve as a part-time adviser rather than continue in a demanding full-time leadership role.
Before joining OpenAI, Simo led Instacart from 2021 to 2025 and previously spent more than a decade at Facebook, now Meta. She became head of the Facebook app after joining the company in 2011.
What is POTS and what symptoms does it cause?
POTS is a disorder involving the autonomic nervous system, which controls involuntary functions such as heart rate, blood pressure and circulation. In adults, it is commonly identified when the heart rate rises by at least 30 beats per minute within 10 minutes of standing, without a major fall in blood pressure.
Symptoms can include dizziness, faintness, fatigue, heart palpitations, nausea, headaches, chest discomfort and difficulty concentrating. Some patients also experience severe exercise intolerance or “brain fog.” The condition affects women more often than men and can overlap with migraine, Long COVID and myalgic encephalomyelitis or chronic fatigue syndrome.
Diagnosis can take years because symptoms may resemble anxiety, dehydration, heart disorders or other chronic conditions. A large patient survey found a median diagnostic delay of about two years, while some patients waited more than a decade.
How POTS shaped Simo’s health advocacy
Simo has said she lived with unexplained symptoms and consulted numerous specialists before receiving a POTS diagnosis around 2019. Her experience exposed the difficulty patients with complex disorders often face when seeking coordinated care.
She later helped establish the Metrodora Institute to support clinical research into neuroimmune conditions. She also became president of the nonprofit Complex Disorders Alliance, previously known as the Metrodora Foundation, and co-founded ChronicleBio, which aims to build research data for disorders including POTS, Long COVID and chronic fatigue syndrome.
Simo has described these conditions as debilitating but historically overlooked, particularly because they disproportionately affect women. She has argued that stronger datasets and coordinated research could shorten diagnosis times and support new treatments.
Why Fidji Simo supports AI in rare-disease research
Simo’s interest in AI and healthcare comes directly from her own diagnostic journey. Complex chronic illnesses often involve symptoms spread across several organs, medical specialties and years of patient records. That fragmentation can make patterns difficult for individual doctors to identify.
AI could help researchers organise large clinical datasets, identify symptom clusters, discover possible biomarkers and match patients with relevant studies. However, AI tools cannot replace qualified doctors, and poorly designed systems could reproduce gaps already present in medical data.
Simo’s decision also highlights a broader leadership issue: managing a chronic illness through endurance alone may not be sustainable. By reducing her operational workload, she is prioritising recovery while continuing to advise OpenAI and support research into diseases that remain difficult to diagnose and treat.
