The Causes of Depression: "My Own Silence"

By Danling Chen

“The silence depressed me. It wasn't the silence of silence. It was my own silence.”
― Sylvia Plath, The Bell Jar

Like many of her literary peers, twentieth-century American poet Sylvia Plath battled recurring stretches of severe depression, which were punctuated by intense spurts of creative activity. From darkly luminous poetry that spoke of heartrending loneliness, to semi-autobiographical accounts of young women in harrowing downward spirals, Plath’s depression deeply inspired and informed her works.

And yet, at a superficial glance, nothing in Plath’s life appeared to explain the profoundly agonized soul which emerged on paper. She was an ambitious and vivacious personality, who enjoyed critical acclaim and high social standing.

What, then, drove this gifted young writer into the dark depths of her mind; in her own words, “enclosed in a wall of glass”? Was it the stifling confines of society, which prohibited open self-expression, especially for a bright young woman? Was it a biological predisposition carried down through generations of depressed individuals? Or was it a glitch at some fundamental level of the brain?

Modern scientists agree that a variety of factors—social, genetic, biological, psychological—contribute to the complex disorder of depression. However, much like the brain itself, the illness is still shrouded in heavy mystery. There is no single physical attributable cause, only a set of predictive conditions that may predispose some individuals to become depressed.

It is widely agreed that depression stems from differences in neural functioning in the brain. Brain-imaging technologies have implicated several specific brain regions: the prefrontal cortex, the hippocampus, the anterior cingulate and the nucleus accumbens. Depressed individuals perform poorer on tests of executive functions, pointing to abnormalities in the prefrontal cortex, which governs emotional responses through the limbic system. The hippocampus, which stores long-term memory, has been observed to be smaller in depressed patients. The anterior cingulate and nucleus accumbens are involved in the brain’s reward system, regulating pleasure, motivation, and interest in activities. Furthermore, depression is also associated with: changes to the amygdala, which is associated with negative emotions; and changes to the pituitary gland and the hypothalamus, which are responsible for hormone secretion. Scientists have pinpointed five key neurotransmitters—acetylcholine, GABA, dopamine, serotonin, and glutamate—which regulate mood and may play a role in depression. However, it remains to be determined whether these brain abnormalities actually trigger depression, or are merely an accompanying symptom of the illness.

Depression may also follow from difficult life events, such as: the death of a loved one, a significant career setback, health issues, drug use, childhood abuse, or intense daily stress. In addition, gender may contribute to depression, as women are more likely than men to be depressed as a result of hormonal fluctuations. The greatest risk period for depression is immediately after puberty, when sex differences also emerge. Furthermore, studies have shown that depression is strongly linked to genetic heritage and tends to run in families: when one twin is depressed, the other twin is almost four times as likely to be also depressed if the twins are identical twins (as opposed to fraternal twins).

Unfortunately, there is no single established cause, or even trigger, of depression. Instead, depression likely arises from a complex interaction of many causative influences, and it may develop spontaneously at any point in an individual’s lifetime. In the sixty years since Sylvia Plath was diagnosed and began penning her eloquent reflections on depression, understanding of the illness remains limited, and major depressive disorder continues to be stigmatized. Until this aura of fear and suspicion lifts, depressed individuals will be forced to remain in their own silence, quieted by the heavy hand of a misinformed and misunderstanding society.

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