Labor Day has passed, kids are back to school, and peak vacation season is now officially behind us. Did you manage to get away?

If you're like a lot of Americans the answer is probably a regretful no. Not only do Americans get ridiculously fewer paid vacation days than Europeans (if they're lucky enough to have the sort of full-time gig that provides them at all), but we also don't even take the measly holiday time we're allotted.

Project: Time Off, an obviously self-interested but nonetheless interesting campaign from the U.S. Travel Association, tracks how many vacation days Americans don't use, and every year it's the same sad story. In 2018 they found half of us (52 percent) left some vacation days on the table, adding up to a whopping 705 million unused days.

What's the effect of all those workers dreaming of time off but not actually ever getting away for long? A recent survey of more than 1,000 Americans by Allianz Global Assistance (a purveyor of travel insurance) aimed to find out. The answer wasn't pretty.

Less vacation = more depression

Like Project: Time Off Allianz conducts an annual (and also self-interested) survey of Americans' vacation habits, but this year they added a twist to the poll. After identifying respondents who said they thought vacation was important but weren't actually able to get away (what the company gives the catchy label "vacation deficit disorder"), Allianz also administered a clinically valid measure of depression symptoms.

The findings were grim. "Almost one-third (30.4 percent) of Americans with a vacation deficit demonstrate symptoms of mild to moderate depression, while 12 percent would be considered to be suffering signs of moderately severe to severe depression," the survey revealed.

How does that compare to the population in general? Exact numbers depend on which authority you ask and how you phrase the question. According to 2018 data from the National Center for Health Statistics around eight percent of adults report they are currently suffering from depression. The Anxiety and Depression Association of America says 6.7 percent of adult Americans experience a major depressive episode in a given year. Something like 15 percent of people will experience depression at some point in their lives.

Whichever number you choose to look at, however, the comparison isn't good. The rate of depression symptoms among the vacation deprived is significantly higher than in the general population. And as Allianz notes, if you look at it from the opposite direction by asking those with depression about their vacation habits the results are also bad. Depressed people are more likely to say they haven't taken a vacation lately. 

Vacation isn't an extra!

All of which underlines a simple truth that should be obvious but sometimes gets lost in the fog of a busy career: vacation isn't a fluffy extra. It's an essential part of both staying well personally and performing at your peak professionally. So look out for the signs that vacation deprivation is getting to you and book yourself some time away if you notice them. Your mental health demands it.