The Science Behind Those Moody Blues

(Editor’s note: This article from a past issue of Brain World magazineIf you enjoy this article, consider a print or digital subscription!)

There was a long line at the coffee shop, and your shoe broke on the way back home. The dog had an accident on the living room carpet. Again. The client who promised you payment for work submitted last week still hasn’t cut the check, and you just learned that the babysitter you hired for Saturday night can’t make it.

On some days it doesn’t take much to turn a perfectly reasonable mood into a terrifyingly bad one. But the way we see moods — as uncontrollable beasts that take over our minds and bodies — probably causes more damage than the moods themselves. That’s because moods, whether good or bad, are really nothing more than signals sent out by the brain in response to certain conditions. Understanding them and their underlying neurology could actually lead to a better quality of life.


Did you ever experience a day that just kept going from bad to worse, with one negative thing happening after the other? It wasn’t the day — we’re sorry to say — it was you.

Bad moods are often caused by a psychological quirk called “ego depletion.” The idea, conceptualized by Roy Baumeister and Mark Muraven in the 1990s, is that, much like our physical resources, our mental resources are limited too. For example: If all of your patience was exhausted arguing with your spouse in the morning before breakfast, you’re going to have almost none left for the commuter who pushed you aside while getting on the subway.

It’s also why we tend to eat more and less healthy when we’re in the midst of a good old-fashioned case of the grumps. The brain, already tired and overexerted is too occupied with other problems to be able to resist that fatty slice of pizza or luscious dark chocolate.

What’s worse, eating large amounts of unhealthful food just leads to more bad moods. In a study conducted by Penn State earlier this year, researchers found that eating junk food made participants feel worse than they did before they’d indulged in the binge-eating session.

And if you experience feeling anxious about binge eating and start losing sleep about your lack of self control, you can expect another negative mood the next morning because sleep deprivation, as it happens, can lead to some pretty bad tempers as well.

“Moods tend to fluctuate depending on chemical components,” says Virginia Biasizzo, an alternative-health practitioner who formerly held positions at Boston’s Massachusetts General Hospital and the Dartmouth Hitchcock Medical Center. “When people feel happy, they are experiencing a dopamine surge that promotes a balance in neurotransmissions equating to elevated or heightened good feelings. As these chemical levels drop, we are no longer capable of writing the next neurotransmission, and therefore our mood shifts.”


“The intestinal tract houses more than half of a human’s nerve cells,” explains Biasizzo. These nerve cells, found in the gut, resemble those in the brain and are capable of learning, remembering, and producing emotion and feelings. It is for this reason that intestinal nerve cells, or the enteric nervous system (ENS), are often referred to as a “second brain.”

“The ENS utilizes many neurotransmitters also found within the central nervous system, including dopamine and serotonin,” she says. “In fact, more than three quarters of human serotonin levels are found within the gut. The chemical shifts that take place during various emotional states happen not only within the brain but also within the digestive tract. The second brain is linked to depression as it involves the absorption of vital nutrients necessary for balanced chemistry. When we are not balanced, we tend to grow sedentary, and this in turn leads to further malabsorption.”


It’s hardly surprising, but your bad mood can change the way you view the world around you. “The biochemical imbalance of neurotransmitters in our brains causes negative moods and [is] labeled as non-constructive because when we’re in a bad mood, we are unable to correctly process information,” says Cammi Balleck, Ph.D., author of “Happy, the New Sexy”: “When in a bad mood, we focus only on the sender of the message and not the message itself, while people in positive moods will pay more attention to both the sender and the context of the message.” In fact, a 2009 study published in the Journal of Neuroscience showed that being in a bad mood could give a person tunnel vision.

But that’s not all. As it turns out, not only can a bad mood ruin your social relationships (perhaps you shouldn’t have snapped at that co-worker?), but it can also skew your sense of morality. Consider the moral dilemma posed by scientists for years: You’re standing on a footbridge over some trolley tracks and see an out-of-control trolley barreling down on five people standing on the track who haven’t yet seen it coming. Next to you is a fairly large man. As the trolley hurtles toward the five people, you realize that the only way to save the five people below is to push the man next to you off the bridge and into the path of the trolley.


Turns out that the way you answer that questions also depends on your mood. According to a paper published in the journal Cognition, a group of German researchers found that participants in a controlled experiment responded to the question in agreement no matter how it was asked. When they were asked if it was okay to push the man, they said “yes.” And when they were asked if it was better to not push, they also said “yes” — basically, they were being agreeable. Those in a negative mood, however, responded no to all questions. Researchers concluded that moods could be influencing the thought process itself by biasing how we view our choices, resulting in different patterns of moral thinking. And if you’re in a bad mood, you’re also going to pass it on because, as it happens, moods are contagious.


Don’t feel too guilty just yet! Scientists say that while part of your bad mood is your fault, if you’re constantly grumpy, it’s your brain that’s to blame. In 2002, psychologist David Zald of Vanderbilt University led a study that scanned the brains of healthy people. It showed that those who reported having been in a bad mood recently had increased activity in a region of the brain called the ventromedial prefrontal cortex.

“Such a connection does make sense because animal studies show that this region of the brain controls heart rate, breathing, stomach-acidity levels, sweating and similar autonomous functions that have a close connection to mood,” he told the BBC at the time.

But here’s why your grumpy mood can be a good thing: According to the latest research, people who are in a bad mood tend to have better memories and are more accurate in their judgment, precisely because they develop that tunnel vision we talked about earlier. If you’re in a bad mood, you’re more likely to be grumpy and more prone to arguments and, as a result, less gullible. This means you’re also less likely to make decisions based on preconceived notions or stereotypes.

I strongly believe we need moods to allow us to come closer to [our emotional] center and recognize the place where we feel most comfortable,” says Biasizzo. “Moods can actually be terrific learning tools as long as we learn to create healthy patterns that serve us for long-term health rather than create mental health.”

(Editor’s note: This article from a past issue of Brain World magazineIf you enjoy this article, consider a print or digital subscription!)

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