A large study in Sweden challenges the belief that autism is more common in males and highlights delays and biases in diagnosing girls.
Females may be just as affected by autism as males, but boys are up to four times more likely to be diagnosed during childhood, according to a study led by the Karolinska Institute in Sweden.
The research analyzed data from about 2.7 million people born in Sweden between 1985 and 2020. Of these, 2.8% were diagnosed with autism between the ages of two and 37. The researchers found that by the age of 20, diagnosis rates in males and females were almost equal.
According to the study's lead author, Dr. Caroline Fyfe, the gender gap in autism is much smaller than previously thought and is mainly related to the fact that girls and women are often not diagnosed or diagnosed late.
The study showed that boys are diagnosed on average about three years earlier than girls. The average age of diagnosis was 13.1 years for boys and 15.9 years for girls. By the age of 10, boys were three to four times more likely to be diagnosed, while girls “catch up” during adolescence.
The authors say the findings highlight the need to review how autism is diagnosed in girls. The study, published in the journal BMJ, also notes that the male-to-female ratio in autism has decreased over time and with increasing age at diagnosis.
In an accompanying editorial, patient rights activist Anne Cary argues that the disparities do not reflect a real difference in incidence, but are a consequence of systemic biases in diagnosis. She warns that autistic girls are often misdiagnosed with mental health disorders, such as anxiety and depression, due to a lack of appropriate support.
Autism organizations are calling for more awareness and to combat gender stereotypes. According to Dr. Judith Brown of the National Autism Society, women and girls are more likely to “mask” signs of autism, which makes diagnosis more difficult and increases the risk of mental health problems.
Experts emphasize that diagnostic services need to be better adapted to recognize the different forms of autism in girls and women, so that they have equal access to diagnosis and support.