Major depression is a common problem among adults -- that persistent feeling of worthlessness and despair that may last weeks, months or years. In America alone, 15 million adults deal with major depression every single year [source: Simon].
Researchers are examining many possible causes, and one they're taking a closer look at is the role that hormones play in adult depression.
Hormones are chemical substances produced by glands of the endocrine system that travel throughout the body, delivering messages to tissues and organs that help regulate their function. Glands that produce hormones include the brain's hypothalamus and pituitary glands, as well as the thyroid, adrenal glands, ovaries, gonads, pancreas and parathyroid. The hormones produced by these glands maintain a delicate balance between your body's functions. Nearly everything is affected by hormones -- your mood, your physical development, your appetite and your fluctuating energy levels, to name a few of the big ones.
Hormones have profound effects upon our sense of well being [source: MedlinePlus]. The hormone oxytocin makes us more cooperative, influences maternal behavior and increases trust, while testosterone makes us less cooperative and more self-serving [source: Preidt]. In testosterone's defense, it also increases motivation and self-confidence, not to mention the sex drive [source: Mayo Clinic].
When hormonal levels fluctuate or certain hormones are over- or under-produced, the important messages hormones send are effectively muted -- or screamed at top volume. Due to the heavy burden of responsibility that hormones carry, any disturbance in their normal levels or functioning can cause all sorts of chaos in the mind and body.
For example, women with elevated levels of the hormones estrogen and testosterone ("sex hormones") following menopause are at increased risk of breast cancer [source: BioMed Central]. Too much human growth hormone -- injected to increase athletic performance and to slow the effects of aging -- can cause heart disease and (ironically) muscle weakness [source: Medical News].
Hormones affect our sleep patterns, our sense of hunger or fullness, energy levels and more. But are hormones responsible for depression?