Depression, which differs from the normal grief caused by the loss of a bodily function or death of a loved one, is best understood by viewing it as a reaction to self-esteem, the feeling that one has about oneself. Depression is the emotional correlate of a partial or complete collapse of self-esteem since it feels unable to live up to its aspirations: to be loved not inferior, to be strong not weak, and to be good and loving not aggressive. Depression stems primarily from mental tension while elation is the expression of an actual or imaginary fulfillment of a person's aspirations.
Basic depression represents a mental state characterized by a lowered self-esteem, a feeling of helplessness, a more or less inhibition of functions, and a more or less intensely felt particular emotion. Basically, depression represents an affect state in terms of helplessness and inhibition of functions.
There are similarities and differences between depression and boredom. With depression the unconscious goals are maintained as in boredom but in boredom the ability to reach them is interfered with by the repression of the true goals and rejection of substitutes because they are either inadequate or prohibited. This results in a lack of direction, the inability to bring about goal directed behavior, and subsequently a feeling of emptiness and boredom.
In depression the mind is shocked into passivity not because there is a conflict regarding goals but because of its incapacity to live up to its aspirations. Depression is the human way of reacting to frustration and misery whenever the person finds themself in real or imaginary helplessness against overwhelming odds with the most frequent factor predisposing to depression being the adult's early life experience during which they really are dependent and helpless.