Compared with controls , children who had ADHD had higher odds of externalizing ( odds ratio -LSB- OR -RSB- , @ ; @ % confidence interval -LSB- CI -RSB- , @-@ @ ; P < @ ) and internalizing ( OR , @ ; @ % CI , @-@ @ ; P = @ ) disorders ; poorer reading ( effect size , -@ ) and mathematics ( effect size , -@ ) performance ; and more peer problems ( P < @ ) .