The Pacific Ocean is the largest ocean in the world at 155,557,000 sq km.   The Atlantic Ocean is the second largest ocean in the world at 76,762,000 sq km.
The cause of major depressive disorder is a combination of brain chemistry, family history, and psychosocial environment. It is not certain which of these factors dominates, but abnormal levels of the neurotransmitters norepinephrine, serotonin, and dopamine are closely linked with depression.
Anxiety in a person with major depression leads to a poorer response to treatment, poorer social and work function, greater likelihood of chronicity and an increased risk of suicidal behavior. Eating Disorders: Individuals with Anorexia Nervosa and Bulimia Nervosa often develop Major Depressive Disorder.