Dr. Matt Walker

The way I think about the difference is the following.

Timescale.

Emotions are short, punctate events that usually last anywhere from seconds to many minutes.

Mood states, however...

like anxiety or depression, those operate on a slightly different timescale from minutes to hours to months to years.

And so it's very unlikely that we can experience an emotional reaction that from a sort of a chronometry point of view,

lasts for two years, but you can certainly see someone who has a mood state abnormality of depression that lasts for several years or who has been chronically anxious for several years.

And I'll come back to why I think that distinction is relevant for a second.

To your point though, about the relationship with sleep, here again, it's a very strong bi-directional relationship.

And I would say that

Probably in the last eight or nine years, we've been doing a considerable amount of work in sleep and anxiety rather than just sleep and basic emotional reactivity.

What we found is it's very strongly bi-directional, that if you have anxiety, it's very difficult to sleep.

And if you are having difficulty sleeping, it's very likely that you will increase your anxiety.

But before we really unpacked that, we started with a very basic study, similar to those that we've described.

We took a group of people and we were very careful to make sure that they had completely normative levels of anxiety.

They showed no signs of an anxiety-related disorder.

And by the way,

Anxiety disorders are, it seems, one of, if not the most common of all psychiatric conditions, just to put it in context for people listening.

And these individuals, no signs of anxiety disorders whatsoever.

They were normative.