Here’s Why You Feel ~Off~ After The Holidays, According To Science

Grey days, the depressing ritual of cleaning up holiday decorations, the realities of returning to work, and weeks of cold weather still ahead: January gives April a run for its money as the cruelest month. If you feel low, fatigued and incapable of getting out of bed in the post-holiday period, you're not alone. "Post-holiday slump" is a real phenomenon, and it's got an interesting psychological explanation: it's based on the chemical comedown from the 'high' that is the holiday season.

The key to understanding the post-holiday slump is dopamine. "Dopamine is a neurotransmitter, a chemical that carries signals within the brain. Among its many duties is a crucial role in signaling the feelings of enjoyment we get out of life’s pleasures," writer Ed Yong explained for Discover magazine. It's a key part of the brain's 'reward center', which affects how we react to good experiences — and, according to a study in 2011, bad ones, too.

When you have an experience you love, or even when you anticipate something you're excited about — a future holiday, singing carols under the tree, tasty Hannukah treats, or working in a soup kitchen over the festive season — dopamine pathways activate the reward center of the brain, and cause feelings of happiness and fulfillment. This isn't all that dopamine does, but it's one of its most famous functions. The holidays are full of lots of rewards for your brain, including sugary foods, alcohol, and new sensations and items; the pleasure center particularly responds to novelty.

Unfortunately, there's a downside to all this fun. When the exciting season is over and you're back to a regular routine, the resulting lower dopamine levels can lead to a mood crash. "Low levels of dopamine are linked to reduced motivation and decreased enthusiasm for things that would excite most people," Healthline wrote. The effect is particularly pronounced in people who already have mood disorders. Studies have found that mental health-related ER visits decrease during the holidays, but rise immediately afterwards, according to The Guardian.

For the majority of people, the post-holiday slump isn't a long-term problem. "Fortunately for most of us, healthy brain neurosensors keep dopamine at manageable levels," Oxford Science Editing wrote. "But too much of a good thing can lead to a crash, much like withdrawal from a powerful drug. Even the most regulated brain cannot avoid the gloomy effects that a major change in dopamine levels can cause. When all the presents are unwrapped and we’re sitting around in a post-merriment torpor, the departure of all those feel-good chemicals can feel terribly gloomy."

For some of us, the holiday season itself can also be stressful. The American Addiction Centers cite statistics that show 45 percent of American adults would skip the season if given the choice, because of concerns about money, family and stress. Even for those of us who love the holidays and find the whole month of December delightful, celebrations can be tired and stressful, with travel, lots of family interactions, interrupted sleep patterns and daily routines, and other issues. "We all feel stressed from time to time, but the holidays offer their own special stressors that can make us feel even worse," the American Psychological Association wrote. The post-holiday slump can be the expression of a build-up of stress and emotional fatigue that's been collecting over some time and, come January, finally has space to come out.

So how do you get over it? Use dopamine's qualities to help out. Plan a new vacation or something similarly fun to get you through the dark days of January, and kick-start anticipatory dopamine. The dopamine lift you'll get from looking forward to the future will give you a boost, even when sorting out your laundry and putting away the holiday lights. Even if you don't book a vacation or join an exciting new venture straight away, it'll still help to scroll through exciting ideas for January — and beyond.