It’s the time of year for cloudy skies and bitterly cold, a good explanation for our winter misery. And the fact that you find yourself whipping out your wallet to combat the “winter blues” is no coincidence.

Yes, it’s refuge from undesirable weather and more active than watching television on the couch all day (what with all the credit card swiping), but there is a biological explanation for the mood change and urge to fill voids with the latest apparel.

Winter blues

Seasonal affective disorder or “winter blues” is scientifically explained as a winter depression caused by little exposure to sunlight, said Steve Ilardi, clinical psychologist and Kansas University associate professor.

With the shorter, colder days, people avoid the outdoors, often going stretches of time without any direct sunlight. This leads to an imbalance of mood-regulating chemicals in the body.

A creative window display tries to entice passersby to shop for sale items at Weaver's Department Store, 901 Massachusetts St., on Tuesday, Jan. 14, 2014.

The retina of the eye has specialized photoreceptors that only fire in the presence of bright light. Indoor lighting is 100 to 200 times dimmer than direct sunlight, Ilardi said.

These light receptors, Ilardi explained, have a connection to circuitry within the brain’s hypothalamus, which regulates our body clock, keeping our biological rhythms, like hormone levels, energy and sleep, in sync.

Sunlight also triggers the mood-regulating neurotransmitter serotonin. Less stimulation leads to depression. Scientific evidence shows overall serotonin-based signaling drops significantly in the winter.

“If you are sunlight-deprived, as many of us are during the winter, the serotonin-based signaling in the brain drops,” Ilardi said.

Reduced serotonin also affects impulsiveness, causing people to engage in impulsive acts like violence, for example. Or even compulsive shopping.

“One of the interesting consequences of being cooped up in the winter is not just that we are stir crazy and we want to get out, but don’t want to go outside because it is cold and cloudy and dark so we head to the mall,” Ilardi said. “But because of serotonin alterations, we are more likely to be impulsive.”

Why retail therapy feels so good

The act of shopping itself provides a distraction from the tendency to brood on troubling thoughts, or rumination.

“We are looking for things that we think we need or things that we wanted, and it’s a very absorbing activity,” Ilardi said.

When people feel stressed, they tend to focus their attention on thoughts related to worry, loss or rejection.

“When a person engages in so-called retail therapy, there is a pretty high likelihood that they are going to break out of that ruminative pattern for a little while,” Ilardi said.

Our inner “hunter/gatherer” heads into the store focused on locating a desired item. When we purchase that item, the neural circuits related to reward activates and lifts our moods, Ilardi said.

“The brain is saying you have just done what you set out to do,” he said.

Not all people who engage in retail therapy are compulsive shoppers, but like other addictive behaviors, long-term effects are harmful, Ilardi said.

“I will say that there are some interesting similarities between compulsive shopping as a mood-elevating strategy and engaging with an addictive drug,” he said. “The effects on the brain are not completely dissimilar.”

Like alcoholism, or binge gaming, shopping to excess is another self-soothing behavioral addiction that only delays problem solving, causing more anxiety later.

The dorsolateral prefrontal cortex of the brain helps us reason short-term gain versus long-term consequences.

If you sit down and make a deal with yourself to spend a certain amount of money without the temptation in front of your eyes, Ilardi said, you listen better to the DLPFC.

“It’s much harder to make a rational, long-term decision when we are at the store, and five pairs of shoes are right there in front of us,” he said. “In that moment while we are looking at those five pairs of shoes, we are put in the mind of what are the immediate benefits of buying these five pairs of shoes.”

The credit card has done us wrong, as well, convincing us that we are shopping at no cost when we may not actually have the money to spend.

“Paper currency as a tangible asset, the brain registers that as ‘this is painful,'” Ilardi said.

“In compulsive shopping, a person just hands over a credit card. What they are able to do in the short term is enter into a temporary state of ‘psychosis’ almost.”

But why shopping?

Marketers would never admit it, but they condone impulsive shopping through advertising, said Noelle Nelson, KU assistant professor of business.

Through phrases like “you deserve it,” or offering self-esteem boosting products. It might not meet immediate needs, but it is effective later.

“By marketing to your emotional side, those are the things you will recall later when you’re in a bad mood,” Nelson said.

Widely accepted stereotypes suggest only women engage in retail therapy, but men are victims too. Marketing researchers, however, know more about how women deal with negative feelings, Nelson said. Women are less protective about how they seek comfort.

The difference is in type of products we seek, generally related to our status or identity. We won’t seek out needs, like groceries or gas.

For women it tends to be clothing, but that’s not to say men who take pride in their clothing wouldn’t get the same lift. More often it may be electronics or gadgets for men. Or the quintessential midlife crisis purchase of a fancy car, Nelson said.

“A midlife crisis is often that you are feeling low self-esteem, you’re feeling kind of badly about where you are in your life,” she said.

New car, self-perceived higher status and no regrets.

“It’s almost as if you excuse yourself because you were having a bad day,” Nelson said. “If you were in your right mind and you were feeling good, and you overspend, it makes sense that you would regret that more because you don’t have an excuse.”