Conduct disorder can be diagnosed in young children and adolescents I thought? Antisocial disorder is sometimes the outcome of a child who had conduct disorder. (It can manifest into various Axis 1/Axis 2 disorders later on, though, not only antisocial)

I just googled and found that it's called "Temper Dysregulation Disorder with Dysphoria" and it's to separate classical cases of bipolar in children and another marker since the dx for bipolar in children has increased. These subset of children don't have a higher chance of having bipolar disorder as adults.