Kanaye has an erratic sleep cycle each month, regardless of which actions he takes. A typical cycle follows: Week 1: falls asleep around 6:00 P. M. and wakes around 2:00 A. M. Week 2: goes to sleep around 10:00 P. M. and wakes around 6:00 A. M. Week 3: cannot fall asleep until around 2:00 A. M., and then wakes around 10:00 A. M. Week 4: unable to fall asleep until 6:00 A. M. and wakes around 3:00 P. M. The appropriate diagnosis in this case is: