Simone Biles will not contest the all-around final at the Tokyo Games "in order to focus on her mental health," USA Gymnastics has said.
The 24-year-old Biles withdrew from the all-around team final on Tuesday but had left her participation in Thursday's individual competition open.
"After further medical evaluation, Simone Biles has withdrawn from the final individual all-around competition," her federation said.
"We wholeheartedly support Simone's decision and applaud her bravery in prioritizing her well-being. Her courage shows, yet again, why she is a role model for so many."
Biles, a four-time Olympic champion from Rio 2016, was seeking to become the first woman to win consecutive all-around titles at the Games since Vera Caslavska of Czechoslovakia in 1964 and 1968.
Simone Biles outlined the importance of athletes' mental health as she talked through her decision to sit out the women's team all-around final on Tuesday.
The gymnastics superstar's first final of the Tokyo Olympics attracted plenty of attention at the Ariake Gymnastics Centre, beginning a bid for a record-breaking six golds at one Games.
But the United States could only secure silver after Biles bowed out following her first routine.Biles opened up on the reasons for departure following the event, which was won by the Russian Olympic Committee.
Asked if she was injured, Biles said: "No, just my pride is hurt a little bit."
The 24-year-old added she was "fighting demons" and explained: "I just don't trust myself as much as I used to. I don't know if it's age. I'm a little bit more nervous when I do gymnastics. I feel like I'm also not having as much fun."
At a Team USA news conference, Biles offered a more positive message, following in the footsteps of Japan icon Naomi Osaka, who withdrew from a series of high-profile tennis events to preserve her welfare before representing her country in the Olympics on home soil.
"I say, 'put mental health first'," Biles said, asked if Osaka's stance was inspirational.
"Because if you don't, you won't enjoy sport and won't succeed as much as you want to.
"So it's okay sometimes to sit out the big competitions to focus on yourself, because it shows how strong a competitor and person that you really are, rather than just battling through it."