The likelihood that an autistic person has another condition correlates strongly with the age at which they received their autism diagnosis. Also, autistic girls are more likely than non-autistic girls to have other conditions, to a degree not seen in autistic boys. The study assessed whether an autistic person’s age, age of diagnosis or birth sex changed their chance of having any of 11 commonly co-occurring conditions, including epilepsy, anxiety and attention deficit hyperactivity disorder (ADHD). The findings may suggest that young men and women are not diagnosed with autism unless they also have another condition, the researchers say. Still, they urge caution when interpreting the results.