On February 26, 2026, Hieu Pham—a member of the technical staff at OpenAI—announced his departure from the company on X in a post that immediately drew attention from the global tech and AI industry.

Pham joined OpenAI in August 2025, about seven months ago, according to his LinkedIn profile. Before that, he was at Elon Musk's xAI from August 2024, and before both, at Google Brain and AugmentCode. His work sits at the frontier of what the industry builds.

In his post he cited being burnt out and railed against a movement within the tech industry that had scoffed at mental health, which he said he had been a part of. “All the mental health deteriorating that I used to scoff at is real, miserable, scary, and dangerous,” he said in the post.

Here is what he said, in full:

"I have made the difficult decision to leave @OpenAI. Working here and at @xai before was a once-in-a-lifetime experience. I have met the best people. Not the best people in AI. Not the best people in tech. Simply the best people. At these companies, I have helped creating extremely intelligent entities that will meaningfully improve our lives.”

“The work makes me proud. But the intensive work came with a price. I cannot believe I would say this one day, but I am burnt out. All the mental health deteriorating that I used to scoff at is real, miserable, scary, and dangerous. I am going to take a break from Frontier AI labs, and will take my family to my home country Vietnam. There, I will try something new, and also search for a cure for my conditions. I hope I will heal. Until then."

He is not moving to another lab. He is stepping away from frontier AI entirely.

Pham's departure lands in the middle of a wider pattern. Earlier this month, Mrinank Sharma, who led the Safeguards Research Team at Anthropic, resigned publicly. In a letter on X, Sharma wrote, "We appear to be approaching a threshold where our wisdom must grow in equal measure to our capacity to affect the world, lest we face the consequences."

At xAI, two co-founders—Tony Wu and Jimmy Ba—posted their departures within 24 hours of each other, bringing the total number of departed xAI co-founders to six out of twelve. OpenAI also disbanded its mission alignment team—a seven-person unit—while also firing a policy executive who opposed its "adult mode" feature.

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TechloyDamilare Odedina