Melatonin and darkened room needed to modulate sleep cycle.

It's hard to believe that Norweigians wouldn't have figured out how to alleviate this type of thing with a good curtain to block out light and perhaps some melatonin or 5HTP which is a melatonin precursor. Sounds like the opposite of the winter time problem with very short days. In that case, full spectrum lighting could help.

But you're probably right, this is what's going on it seems.