Has the attention deficit hyperactivity disorder phenotype become more common in children between 2004 and 2014? Trends over 10 years from a Swedish general population sample.

We found no evidence of an increase in ADHD-like traits at the extreme end of the distribution from 2004 to 2014, but small increases in normal and subthreshold variations of ADHD-like traits were observed. This suggests that the increased rates of clinically diagnosed ADHD might reflect changes in diagnostic and treatment practices of ADHD, administrative changes in reporting diagnoses, greater awareness of ADHD, better access to healthcare, or current overdiagnosis, rather than an increase in the ADHD phenotype.