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.
Depressed mood, guilt, self-harm, agitation, distractibility, apathy, and impaired executive functioning are all part of the diagnostic criteria for major depressive disorder. As expected, these classical symptoms of major depression decreased as my patients recovered.