I'm quite sure.  I got mono a couple of years ago 
and it really fucked up my sleep cycles--opposite 
of what mono is supposed to do.  Instead of 
sleeping all the time, I was super hyper and 
would go to bed at 5am for no other reason than I 
was bored because everyone else was asleep and 
get up a 7 or 8 and run across campus for my 
first class.  Now I'm all better, but I'm still 
weird because I'll actually start dreaming before 
I fall asleep completely, but since the crucial 
part of sleep is REM/dreaming sleep, and I still 
get plenty of that, I'm fine.  

I bet there's lots of cel collectors on this 
forum who wish they could do the same so they 
could stay up all night for cel updates and feel 
fresh as a daisy the next morning to go to work. 
^_^

*cof cof*  now lets end this line of conversation 
before it goes off the screen.