Between the crazy headlines, post-holiday season social and financial hangovers, lack of natural light and colder weather, it can be really tempting to cancel all your plans, grab your remote, dive beneath a weighted blanket and ride out the rest of the winter. “If it’s not interfering with your relationships, then social withdrawal is a natural rhythm. We did develop all these winter holidays with bright lights and a lot of enticing food and social activities to combat this stuff — people have been doing it for centuries,” says Kathryn Roecklein, Ph.D., assistant professor, Psychology, University of Pittsburgh.

Come winter, the urge to hibernate is kind of built into our DNA, says Robert Levitan M.D., Professor, Department of Psychiatry and Department of Physiology, Cameron Parker Holcombe Wilson Chair in Depression Studies, University of Toronto and The Centre for Addiction and Mental Health (CAMH). “Hibernation is an adaptive process which is designed to protect individuals from the challenges of winter time, particularly as it relates to energy regulation, whereas seasonal depression is a combination of those physical changes with other clinical characteristics that are highly problematic for the individual,” Levitan says.

To illustrate how common this urge to pull back a little can be, Levitan mentions a 1999 study where random participants answered a Seasonal Pattern Assessment Questionnaire. Of those surveyed, 92 percent of the subjects reported noticing seasonal changes of mood and behavior to varying degrees. But 27 percent of those surveyed regarded these seasonal changes as a problem.

“There’s this continuum of people, from those with the most severe symptoms to people who don’t change at all, but the line between what is and isn’t (seasonal) depression is a point on the continuum,” says Roecklein. “The person directly just to the left of that point might get a diagnosis, while the person just to the right of that point does not. They’re not that different. There are people who wouldn’t get a diagnosis who seek treatment and benefit from it, and there are people who would get a diagnosis but have barriers to treatment, like income, or stigma or accessibility,” she explains. “So, the difference between those with seasonal affective depression (SAD) and those who don’t could be very little or pretty big, because we see this as a continuous distribution.”

So how can we tell if our overwhelming urge to hibernate has crossed over that point? Both Levitan and Roecklein shared what to look out for:

1. Your need to hibernate interferes with your work and social life

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It’s one thing to want to hide from the world for a minute and binge watch something, it’s another entirely when you call in sick to work or cancel plans with friends more than a couple of times. “If you’re avoiding doing work or social circumstances, that’s what a lot of addictive behavior is — avoidance. At that point it becomes a problem and needs to be assessed by someone,” Levitan says.

2. You’re sleeping too much or too little

“No one with SAD says they aren’t tired,” says Roecklein, adding that a SAD-inflicted sleep disturbance can involve insomnia or sleeping too much. “Light, which is reduced in winter, is perceived in the retina and information about that light travels to your circadian clock, and also to sleep centers in the brain. These neuropathways about light levels can directly influence sleep. Think about it: if you were to take a really important exam, would you prefer to do it in a reasonably well-lit room or in a dim room? Neurotransmitters regulate sleep onset, so it could be a function of the neuro-signaling in your brain. Let’s say you got a full night’s sleep but you’re in a dimly environment all day. You’re going to feel tired. That’s kind of like what this retinal pathway is like. It’s keeping your brain in the dim light, so it’s hard to remain alert and wakeful,” she explains, adding if you find it hard to mentally power down and are sleeping 1 to 2 hours less per night, or, conversely, if you’re sleeping 1 to 2 hours more a night including naps, it might be time to seek help.

3. You gain or lose weight in a relatively short period of time

After the holidays, it’s common to put on a couple of pounds. But if you can’t stop eating whatever whenever, that’s another thing. “Individuals who already have challenges with eating behavior and weight regulation are at higher risk for reacting to the seasonal changes in a more extreme way,” says Levitan. SAD-induced weight gain can result from caving to carb cravings, which are very common this time of year. “It’s usually sweets or starches,” says Roecklein. “But you just can’t literally eat donuts all day.” Fewer people tend to experience a loss in appetite but it does happen, she adds.

4. You withdraw from social situations

Both Levitan and Roecklein say social withdrawal is a key red flag that your urge to hibernate might be due to SAD. “Social withdrawal is just a symptom of depression,” Roecklein says. “We definitely see a whole range, from people who don’t change their social activity at all to those who drastically reduce their interaction with others, even when its necessary at work or at home.”

5. You’ve lost interest in things you normally enjoy

“If you usually go to the gym three times a week and now you don’t, or if you usually enjoy cooking and you just don’t, those are the first things we look at,” says Roecklein.

Both clinicians urge anyone with suicidal thoughts to seek help immediately.

SAD can be insidious because, as Roecklein mentioned earlier, the fine line is hard to pinpoint. “You might assume that it’s just nothing and before you know it, you’ve missed a lot of work,” says Levitan. “It starts gradually and gets better gradually. It’s like the frog that gets cooked because he doesn’t notice the water getting warmer,” Roecklein says. “The difference is going to come down to whether your urge to hibernate interferes with your job, your home, your relationships or your health,” Roecklein says. “[SAD] does impact your life. So if you want to have more energy, sleep better, do more exercise, see your friends and get more done, do something about it.”

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