The leader of the long-running study said that the drugs did not improve mental health in children with gender distress and that the finding might be weaponized by opponents of the care.
An influential doctor and advocate of adolescent gender treatments said she had not published a long-awaited study of puberty-blocking drugs because of the charged American political environment.
The doctor, Johanna Olson-Kennedy, began the study in 2015 as part of a broader, multimillion-dollar federal project on transgender youth. She and colleagues recruited 95 children from across the country and gave them puberty blockers, which stave off the permanent physical changes — like breasts or a deepening voice — that could exacerbate their gender distress, known as dysphoria.
The researchers followed the children for two years to see if the treatments improved their mental health. An older Dutch study had found that puberty blockers improved well-being, results that inspired clinics around the world to regularly prescribe the medications as part of what is now called gender-affirming care.
But the American trial did not find a similar trend, Dr. Olson-Kennedy said in a wide-ranging interview. Puberty blockers did not lead to mental health improvements, she said, most likely because the children were already doing well when the study began.
“They’re in really good shape when they come in, and they’re in really good shape after two years,” said Dr. Olson-Kennedy, who runs the country’s largest youth gender clinic at the Children’s Hospital of Los Angeles.
That conclusion seemed to contradict an earlier description of the group, in which Dr. Olson-Kennedy and her colleagues noted that one quarter of the adolescents were depressed or suicidal before treatment.