As for a personal anecdote, I've experienced both ends of the sleep spectrum: in the past couple years I've had two 4-month long periods where I required little to no sleep to function as well as I ever have in both work and social settings. My personal belief is that this can be chalked up to a healthy diet, constant exercise, and an abundance of happiness. Also, I caution those who pine for the ability to function on less sleep: as the lady in the article mentions, it can absolutely cause issues in one's relationships. Other than that however, all positives in my experiences.
On the flip side, I've dealt with multiple bouts of varying degrees of depression that have caused my daily hours of sleep to skyrocket to ~10-12 hours/day. After experiencing both ends of the required sleep spectrum I'm convinced that, at least for me personally, happiness and health plays a huge role.