Generally human body is designed to Sleep at night and work during the day. So messing up with this predefined schedule could prove costlier in terms of health hazardness.
Some of the points which you might be interested peeping at regarding the consequences of change in Sleeping pattern:
1) Nocturnal schedule places you at greater risk of Diabetes, Heart Diseases and Gastrointestinal illness
2) Disturbance in REM cycle
3) Disturbance in Circadian rhythms
4) Causes Colon Cancer
5) Causes Alzheimer’s disease
6) Strange behavioral traits have been found such as Depression, Fatigued, Memory Loss, Short-Tempered and Weight gain