JMany parents wonder what the difference is between a developmentally appropriate temper tantrum and a temper tantrum that is out of the range of “normal” child behavior. In the January 2008 issue of The Journal of Pediatrics, researchers compared the temper tantrums of children who had been diagnosed with depression and disruptive behavior disorders to children without disorders. It was found that children with mental health diagnoses had more aggressive tantrums and had tantrums that lasted for a longer period of time. Children with depression were more likely to have self-injurious behavior during tantrums.

http://www.medicalnewstoday.com/articles/92215.php

When most children have tantrums, if the parent walks away or ignores the behavior, the tantrum stops fairly quickly. However, other children continue to have a tantrum, even to the point where it lasts more than one hour. It is very difficult for these children to soothe themselves. If your child has temper tantrums that last for an extended period of time or if there is any self-injurious behavior that occurs, seek professional help.