Many of the ordinary problems that children have can be dealt with by a paediatrician who has some developmental or behavioural experience. These would be minor problems with eating or sleeping, tantrums, or even hyperactivity. Many paediatricians are quite skilled in the first and second line drugs for impulsive and hyperactive behaviours.
Persistent behavioural difficulties including hyperactivity, severe impulsive behaviour, oppositional behaviour, aggression, or self injury, is the kind of treatment that will require the attention of a specialist in behavioural psychology or a child psychiatrist who has experience with the developmentally disabled. Sometimes, individuals may need referral to an epilepsy specialist first, if there is suspicion of seizures underlying the behavioural difficulties. But the long-term treatment of serious behaviour or emotional problems in individuals should almost always be the responsibility of a specialist in child and adolescent psychology/psychiatry, who has the appropriate background.