Complex sentence: It has been shown that chronotype is related to the effect of sleep deprivation on mood in normal people: those with morningness preference become more depressed following sleep deprivation while those with eveningness preference show an improvement in mood.
Split into simpler sentences: It has been shown that chronotype is related to the effect of sleep deprivation on mood in normal people. Those with morningness preference become more depressed following sleep deprivation while those with eveningness preference show an improvement in mood.