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.
Depression is a mood disorder that causes a persistent feeling of sadness and loss of interest. Also called major depressive disorder or clinical depression, it affects how you feel, think and behave and can lead to a variety of emotional and physical problems.lso called major depressive disorder or clinical depression, it affects how you feel, think and behave and can lead to a variety of emotional and physical problems.