Dr. Matt Walker

They don't get a positive good feeling.

Now, if you're someone who is healthy and you're sleep deprived, you go too far in the reward direction and you become vulnerable to reward and sensation seeking.

But if you're depressed and you're shifted to sort of away from that and sleep deprivation brings you back closer to a normative reward-based reactivity, maybe that's the reason why you get this antidepressant benefit and why when you start sleeping again,

you take away that enhanced reward sensitivity and you lose the antidepressant benefit.

So I think we still don't know enough about depression and sleep yet.

If you were to ask me of the four, quantity, quality, regularity, and timing, which would be ideal?

I would say all four are definitely players, but timing may have some of the best evidence because it's not just about sleep when it comes to depression.

It's also about your circadian rhythm, that if you are not aligned with your natural chronotype, your natural 24-hour rhythm, circadian misalignment when you fall out of synchrony with your natural chronotype,

is a strong predictor of depression.

So if there is an actionable item, first, it would be to say from a big picture perspective, understand that sleep is one of the

available options for you as a no cost to try to stabilize your mental health.

Now, I'm not suggesting that all psychiatric conditions are sleep disorders.

That's not true.

And I'm not suggesting that you should stop

simply at the place of getting your sleep straight to help with your mental conditions.

Not at all.

I am saying, however, that if you do get your sleep straight, it's only going to help and may help quite a significant amount based on the data.

But when it comes to depression, I would say of those four, QQRT, there's a very strong emerging data that circadian misalignment, not matching your chronotype to the time when you are sleeping and the time you are awake,

is one of the strongest factors.

So if you want to say, I can't do all of them, Matt.