Decision Making in Narcolepsy

I am interested in the scientific studies that have been conducted related to narcolepsy and came upon this study that showed a reduced ability in narcoleptic patients to exhibit perseverance and good decision-making.

Perhaps, this study can explain why many narcoleptic patients also suffer with depressive illness. A question of which came first, the chicken or the egg. I have battled with depression several times in my life. I'm okay right now, but the medications used to control cataplexy often reduce the ability to show emotion. That's me.