As if narcoleptics didn’t have it hard enough with a neurological disorder that can cause excessive daytime sleepiness, sudden muscle weakness and uncontrollable episodes of falling asleep, they also have a rate of depression that is six times higher than the general population.

But new research suggests this may be no coincidence. We’ve known for about a decade that narcolepsy is caused by an absence of neurons in the brain that produce hypocretin (HI-pockreh-tin), a chemical that regulates arousal and wakefulness. However, in addition to regulating sleep, it seems that this neurotransmitter is also helping govern emotion, particularly pleasure and anger.

Scientists found that hypocretin levels fall when people are stressed or in pain and spike when they engage in pleasure-seeking activities, like socializing, eating or watching TV. This all suggests that your brain wants to keep you awake to experience pleasure and seek rewards.

For narcoleptics, however, a lack of hypocretin can also mean a lack of interest in seeking pleasure — a symptom of depression. Because of this, narcoleptics are abnormally resistant to becoming addicted to drugs — a fact that could lead to breakthroughs in addiction research.

When they experience strong emotions, some people with narcolepsy fall down or experience temporary paralysis. Called cataplexy, this phenomenon can also be linked back to hypocretin. While gut-wrenching laughter would normally cause a surge of the chemical, it’s essentially absent in narcoleptics, who tend to collapse. This suggests that hypocretin may also help regulate muscle control when our feelings run rampant.

Hypocretin may eventually be the key to treating narcolepsy, but it also gives us new insight into the human brain — and that’s nothing to lose sleep over.