Doctors have long known that autism is much more common in men than in women. However, they still don’t know why. The link between testosterone and autism, long considered, would not be established.
Genetic mutation, high levels of estrogen during pregnancy, … From study to study, the scientific community has evoked, in recent years, many possible causes of autism. One thing is certain: boys are more affected than girls. But the “why” has not yet been fully understood.
When a disease affects men more, testosterone is one of the prime suspects. But a study, published in the journal Proceedings, does not establish a link between this hormone and cognitive empathy. This ability to read and understand the emotions of others is impaired in people with autism.
643 participants for the largest study of its kind
“Several previous studies have suggested a link between testosterone and reduced cognitive empathy, but the samples were very small and it was very difficult to determine a direct link,” says Amos Nadler, lead study author and researcher at Western. University (Ontario, Canada). For this work, 643 men participated in two randomized controlled studies. This is the largest study of its kind. “Our results show unequivocally that there is no linear causal relationship between testosterone exposure and cognitive empathy.”
Findings Contradict ‘Hyper-Masculine’ Brain Theory
In 2011, a study showed that giving healthy pregnant women testosterone reduced their performance on an emotion reading test. Thus, researchers at the time claimed that prenatal exposure to this hormone created a “hyper-masculine” brain, which later impaired the child’s capacity for empathy. This hypothesis later became one of the main causes attributed to autism. However, only 16 people participated in the study.
Testosterone had no real effect on empathy
For Amos Nadler’s study, 643 healthy men received an application of testosterone gel or a placebo. They then had to answer questionnaires and perform certain tasks to allow the researchers to measure their cognitive empathy. Thus, the scientific team found no link at all between the administration of testosterone and the impact on cognitive empathy. Although the 2011 study only included women and the current study only included men, the researchers say that if testosterone had a real effect, they would have perceived a difference.
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