Quoted from The Hundred Year Lie:

An estimated nineteen million Americans have been diagnosed with depression and treated with pharmaceutical drugs, a number that represents, as a percentage of the total population, an increase of more than 300 percent since World War II. Even if we take into account higher stress associated with changes in lifestyle and work habits over a half century, common sense tells us that something else must be contributing to this upsurge of mood disorders that we see manifested in depression, behavioral and attention problems among children, and antisocial criminal behaviors among teenagers.

Carbohydrate cravings, unexplained weight gain, and fatigue are some of the symptoms associated with a disorder known as atypical depression, which afflicts nearly half of all people diagnosed with depression. A study published in the Journal of Psychiatric Practice during 2005 found a direct link between this form of depression and a deficiency of essential nutrients in diet.

A randomized, double-blind study of 113 people—eighteen to sixty-five years old—with atypical depression found those exhibiting the most intense symptoms tested positive for a chromium deficiency. Those patients in the eight-week study given a chromium picolinate supplement showed “significantly greater improvements” in all symptoms related to their depression. Chromium is a trace mineral in food and is essential to enabling us to metabolize carbohydrates, fats, and proteins. It works as a preventive against diabetes. Normally it would be found in our soils and in foods like whole grains, onions, lettuce, and tomatoes, but depletion of soil nutrients and food processing has taken most of it out of our diet.

“For years, the link between depression, insulin sensitivity, and the value of dietary chromium picolinate has been hinted at in small studies,” declared lead investigator John Docherty, a professor of psychiatry at Cornell University.

Contained within this study we find a revelation that is a smoking-gun indictment of pharmaceutical drug treatments of atypical depression. “The use of antidepressants, mood stabilizers, and antipsychotics that are commonly prescribed to treat depression can often worsen carbohydrate cravings,” revealed Docherty. Other nutritional researchers have pointed out that prescription drugs routinely deplete stores of essential minerals in the body, such as chromium.

These findings strongly suggest that the synthetic drugs millions of people routinely take for depression may be aggravating the underlying cause of their depression. In other words, your cure may be doing more long-term harm than good, while the real cure is the return to a naturally occurring substance that has been depleted from your diet.

Still another link between a naturally occurring substance and depression comes from a massive study of pregnant women in Britain. More than fourteen thousand expectant mothers were recruited, and then the women and their children were monitored for eleven years by the University of Bristol and other collaborators for information about eating habits, experiences of violence, stress, mood disorders, etc.

A major finding was a fiftyfold greater rate of major depression among those women who had the lowest levels of seafood consumption. This finding mirrored results of postnatal surveys from twenty-three countries that found depression occurs less frequently in those countries, like Japan, with high seafood consumption.

The substance in seafood that turned out to be responsible for providing protection against depression was omega-3 essential fatty acids, which cannot be made by the human body and are necessary for the membranes of neurons in the brain. A United States Public Health Service official, Joseph Hibbeln, describes how omega-3s have been replaced in our diet by the less-healthy omega-6 fatty acids from seed oils: “During the four to five million years of human evolution the dietary ratio of omega-6 fatty acids to omega-3 fatty acids was approximately 1:1. However, the omega-3 family (found in fish, seafood, walnuts, leafy vegetables) is getting pushed out of the brain by a huge rise in intake of omega-6 (from meat, corn oil, soybean oil, and other oils). The ratio is now estimated to be in the region of 15:1. Increasing prevalence rates of major depression in the United States are closely correlated to the increasing amounts of omega-6 fatty acids in the food supply.”

As the consumption of omega-3s fell and the intake of omega-6s rose, Hibbeln has documented, a corresponding escalation occurred in the homicide rates of the twenty-six countries studied where statistics for homicides and seafood consumption are kept. A lifetime of nutritional deficiencies can result in a lifetime of depression or criminal behavior.

To avoid coming down with depression or seasonal affective disorder, which impacts an estimated 17 percent of all U.S. residents over the course of a lifetime, experts recommend omega-3 supplements, the herb called Saint-John’s-wort, and the synergistic effects of a healthy, pure-foods diet. “The foundation of a depression-free lifestyle consists of a good diet, a regular exercise and stress-reduction program, and elimination of all chemical addictions,” says Hyla Cass, assistant clinical professor of psychiatry at the UCLA School of Medicine.

Fitzgerald, Randall. The Hundred-Year Lie: How to Protect Yourself from the Chemicals That Are Destroying Your Health (pp. 183-186). Plume. Kindle Edition.