Depression has been classified as a mood disorder or affective disorder. Mood is defined as a pervasive and sustained emotion that, in the extreme, markedly affects a person's perception of the world and ability to adequately function in society. Mood disorders are among the most common encountered in clinical practice and are divided into depressive disorders and bipolar disorders. There are over 187 million adults in the United States – and about 19 million of these people will experience a depressive episode in any given year, making depression the most common psychiatric disorder encountered in general medical practice. Women are two to three times more likely to experience depression than men. Depression is a one-two punch that knocks the sufferer out of the ring on a daily basis. Number one, the symptoms themselves make life miserable. Number two, the depressed individual struggles to function and keep up with the life's normal demands. Conventional treatment for depression is aimed both at reducing symptoms and helping the individual regain the ability to function they once enjoyed. Usually the treatment includes psychotherapy and the use of anti-depressant medications.

The Mediterranean diet is based upon the traditional dietary patterns of the countries of the Mediterranean Basin.  The principal aspects of this diet include high consumption of olive oil, legumes, unrefined cereals, fruits, vegetables, moderate consumption of dairy products (mostly as cheese and yogurt), moderate to high consumption of fish, low consumption of meat and meat products, and moderate wine consumption. More than any other food ingredient, olive oil represents the Mediterranean diet. There is considerable clinical data to show that antioxidants in olive oil can provide additional heart health benefits such as positive cholesterol regulation and LDL cholesterol reduction, and that it exerts additional anti-inflammatory and anti-hypertensive effects in humans.

A study published in the Archives of General Psychiatry has found that people who follow the Mediterranean diet are less likely to develop depression. The researchers followed more than 10,000 healthy adults who filled out questionnaires between 1999 and 2005 and who were free of depression when the trial began. The participants adherence to the Mediterranean diet was measured by looking at nine components, such as low intake of meat, moderate intake of alcohol and dairy products, and high intake of fruits, nuts, cereals, vegetables and fish. The researchers followed-up with the participants after an average of 4.4 years. They found that the overall incidence of depression for those who most followed the diet was 30 percent lower than for those who most ignored the dietary rules. Even lower rates of depression were associated with intake of specific elements of the Mediterranean diet, such as fruits, vegetables and olive oil. The researchers noted that adopting the Mediterranean diet is not appropriate for treating existing depression, but for those with a family history of depression a diet like this probably would be a good place to start.¹

¹ Sanchez-Villegas A, Delgado-Rodriguez M, Alonso A, et al. Association of the Mediterranean dietary pattern with the incidence of depression: the Seguimiento Universidad de Navarra/University of Navarra follow-up (SUN) cohort. Arch Gen Psychiatry. Oct2009;66(10):1090-8.