Facebook's (FB  ) Chief Technology Officer of 13 years, Mike Schroepfer, has announced that he will be stepping down from his position next year. Schroepfer will be replaced by long-time Facebook insider and head of the company's hardware division Andrew Bosworth and will be transitioning to fill the company's first "Senior Fellow" role.

This change in leadership comes fast on the heels of a report alleging that Facebook executives have been aware for years that its platforms have a negative effect on the mental health of their users, especially teenagers and children.

"This is a difficult decision because of how much I love Facebook and how excited I am about the future we are building together," Schroepfer wrote on Facebook. "This change in role will allow me to dedicate more time to my family and my personal philanthropic efforts while staying deeply connected to the company working on key initiatives including recruiting and developing technical talent and continuing to foster our AI investments in critical technologies like PyTorch."

Schroepfer was brought on board at Facebook in August of 2008 before the recession when Facebook was already dominating the market. Since then, the company has made history with the highest IPO in history and a current market cap of just under $1 trillion.

Schroepfer's time at the company accompanied its first major forays into the realm of artificial intelligence. The company has received criticism for its algorithm-fueled news feeds which deliver users content that the site believes they will be interested in based on prior activity. This process relies on data collection and AI, both of which have been flagged as security and privacy concerns by human rights activists.

Schroepfer's exit is the largest shake-up in the leadership at Facebook in some time due to the CTO's close proximity to CEO Mark Zuckerberg.

Zuckerberg wrote in a press release that Schroepfer "has played a critical role in almost everything we've done - from building and scaling our teams to mentoring many of our key leaders, and from helping us develop new technologies like AI and VR to operating our infrastructure and business services at global scale. Schrep and I have had a close partnership over the years, and in addition to being a great leader, he's also a great person and a close friend."

Schroepfer's replacement, Bosworth, has been with the company since 2006 and is known as the creator of Facebook's Reality Labs, a division which he will continue to lead in his role as CTO.