There are quite a few other types of insomnia that can be diagnosed, though they are not as common:
Paradoxical insomnia is when someone is experiencing trouble sleeping, but does not show the normal symptoms that go along with it, which makes it extremely difficult to diagnose.
Sleep-onset insomnia is when someone has trouble falling asleep, but often sleeps a normal amount and usually sleeps rather restfully once they are asleep.
Behavioral insomnia of childhood is when a child’s sleep is disrupted due to them missing something that they usually have or feel they need to fall asleep such as a nightlight or stuffed animal. This is rarely diagnosed anymore, but if you noticed your child is having trouble sleeping, consider if anything has changed for them recently.