In the Mood

Mood is a lot like art. You know it when you see it—or feel it. Like art, it’s a distinctive part of the human experience of the world. And it encompasses everything, which may be why science has such a hard time defining exactly what it is and how it works.

Moods are states of mind linked to emotions but more diffuse, more stable, more enduring. Like emotions, they are thought to originate in the brain’s amygdala, where incoming perception gets emotionally coded, in collaboration with the prefrontal cortex, where emotions are regulated. Moods are also strongly influenced by circadian rhythms, and disturbances in the sleep-wake cycle disrupt mood.

Moods influence many if not all of the brain’s high-flying operations—perception, motivation, decision-making, social interactions, and even such basic cognitive processes as memory and attention. Mood also has a distinct impact on physical health, while physical health, in turn, directly affects mood and its regulation. Metabolism is intimately connected to mood, which powerfully influences the availability of both physical and psychic energy.

Mood, many believe, is a running average of emotional events. But cutting-edge science suggests it is something in its own right—a measure of momentum to engage with the world and expect to get good things from it, especially to learn and grow. Serving the brain’s function as a prediction center about the world, mood, in this view, reflects certainty (or uncertainty) about the effects of one’s actions.

There’s even evidence that people normally regulate their mood instinctively by choosing what activity to engage in next. When they feel down, they look for things to do that will cheer them up—religion, exercise, chocolate, movies. And when they are up, they may risk taking on activities that could bring them down.

British researchers have found that the normal mood-regulating process is impaired in people with depression, the world’s most common mood disorder. Globally, more than 250 million people, including 18 million adults in the U.S., are affected by it. Increasing numbers of the 250 million are children, those whose full-time job to learn and grow is threatened by the disorder.

Conventional approaches to mood disorders focus on manipulating brain chemistry with drugs and
reducing levels of stress, which otherwise let the amygdala run rampant. But those on the clinical front report that people seem increasingly eager to find ways to influence mental function in minimally disruptive ways.

At the same time, science is carving an exciting path to the brain though the stomach, demonstrating the physiological effects of everyday nutrients. There is mounting evidence that many food components, often when concentrated in supplement form—nutraceuticals—have the medicinal power to maintain mental health and even restore it.

For years, population-wide surveys have shown a significant link between dietary factors and mood disorders. The Western diet, heavy on processed foods at the expense of nutrient-rich fruits and vegetables, is consistently associated with high rates of depression. Diets focusing more on fish, produce, nuts, and berries appear to protect against mental disorders and even the cognitive decline of aging.

But doping out exactly which nutrients exert protective effects and how they do it has been challenging, riddled with conflicting results. That’s because there’s no one baseline nutritional status or consumption pattern against which to discern variation in effect of dietary components. Nevertheless, large-scale analyses consistently spotlight several specific nutrients. Chief among them are the B vitamins and vitamin D.

All eight B vitamins tend to act in concert, and all eight get personally escorted across the blood-brain barrier to participate in a number of neurochemical pathways implicated in depression and other psychiatric conditions. Nevertheless, deficiencies in B3 (niacin), B6 (pyridoxine), B9 (folate), and B12 (cobalamin) stand out in studies of depressed people. In one recent study, a team of researchers in Ireland and Germany found deficiencies of vitamins B3 and B6 in a group of patients with depression severe enough to warrant electroshock therapy.

B6 is notably required for the synthesis of serotonin and GABA, both neurotransmitters of calm in different ways. Recent studies have shown that supplementation with vitamin B6 ameliorated depressive symptoms in a group of older patients. Researchers believe that B vitamin status may account for difference in response to antidepressant drugs.

Evidence is growing that low blood levels of vitamin D also modulate mood and susceptibility to depression. It seems to act in multiple ways: stimulating the growth of nerve cells, preserving memory and executive function, while clearing out toxins. No studies establish how much vitamin D is needed for its full effect, but most people in temperatate latitudes don’t get enough of the vitamin from the sun.

It’s not exactly a nutrient, although it is plant-derived and bioactive, but CBD, or cannabidiol, also contributes to equilibrating mood. An oil extracted from marijuana’s cousin, the hemp plant, it takes a completely different, more direct path to mood modulation. It interacts with the brain’s own cannabinoid system to prevent the breakdown, thus prolonging the action, of the naturally occurring calming neurotransmitter anandamide.

But that is not all it does. Studies of both animals and humans show that CBD may lift mood, lower feelings of isolation, relieve social anxiety, alleviate pain, and mitigate PTSD.

Research suggests that in addition to acting directly on the endogenous cannabinoid system, CBD does what all effective antidepressant treatments do—it promotes neurogenesis and synaptic plasticity. That is, it paves new neural pathways of possibility, the very route to rehabbing mood.

Mood Morsels

• In 2017, the latest year of available data, 17.3 million adults in the United States—7.1 percent of all U.S. adults—had a major depressive episode.
• 11 million—4.5 percent of U.S. adults—experienced severe impairment during their episode.
• The prevalence of major depressive episodes is higher among adult females than males (8.7 percent vs. 5.3 percent).
• Depression commonly manifests as sadness, worthlessness, and guilt in women; in men, as irritability, anger, or aggression.
• The prevalence of major depressive episodes among adults is highest among individuals ages 18 to 25 (13.1 percent).
• Adolescents are especially vulnerable to depression; 3.2 million U.S. teens—13.3 percent of the population ages 12 to 17—had at least one major depressive episode.
• The major STAR*D study of depression found that more than 50 percent of those with the disorder do not respond to any medication.