Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Participants included in conventional cohort analyses (steps 1 and 2), sibling comparison analyses (step 3), and sex-stratified sibling comparison (step 4). ADHD indicates attention-deficit/hyperactivity disorder; MoBa, Norwegian Mother and Child Cohort Study.
