Researchers followed 300 children who had the combined type of ADHD. They were part of a large trial called the MTA and were 7 to 9 years old at the start. The study measured how much other children rejected them at about ages 9 and 10. It then looked at how they were doing years later, at about ages 15 and 16.
Children who were more rejected by peers tended to have worse outcomes later. At the 6 year mark this included delinquency, cigarette smoking, anxiety, and trouble functioning day to day. At the 8 year mark only the trouble functioning was still linked. These links held even after the researchers accounted for things like family background and the children's ADHD, defiant, and conduct symptoms. The tie to functioning stayed small but real at both points (β 0.16 at 6 years and β 0.21 at 8 years).
Having a close, mutual friend did not predict any of these later outcomes. It also did not protect rejected children from harm. In one case a friend went the wrong way: among rejected children, those with a friend smoked more (β 0.27), while friendless rejected children did not. The study only looked at the combined type of ADHD and left out children who lacked peer data, so it may not fit girls, racial minorities, or other groups.
Source: Mrug S, Molina B, Hoza B, et al.. Peer Rejection and Friendships in Children with Attention-Deficit/Hyperactivity Disorder: Contributions to Long-Term Outcomes. Journal of Abnormal Child Psychology (2012). doi:10.1007/s10802-012-9610-2