Light effects the hypothalamus section of your brain. Your hypothalamus controls or influences your pituitary
gland. If functions of your pituitary gland are stoped or slowed they cannot perform important functions. These
important functions control a lot of what would "control depression".
And my explination:
Hypothalamus is proven to be responsive of light and it causes a lot of disorders:
"through its action on the pituitary, controls body temperature, hunger, thirst, fatigue, childbirth, emotions,
growth, milk production, salt and water balance, sleep, weight, and circadian cycles."
(http://www.jonbarron.org/natural-health/endocrine-hypothalamus-pituitary-pineal-gland)
This is confirmed again:
Hormones secreted from the pituitary gland help control the following body processes
- Growth (Excess of HGH can lead to gigantism and acromegaly.)
- Blood pressure
- Some aspects of pregnancy and childbirth including stimulation of uterine contractions during childbirth
- Breast milk production
- Sex organ functions in both men and women
- Thyroid gland function
- The conversion of food into energy (metabolism)
- Water and osmolarity regulation in the body
- Water balance via the control of reabsorption of water by the kidneys
- Temperature regulation
- Pituitary gland also makes endorphin to relieve pain and alter mood.
(http://en.wikipedia.org/wiki/Pituitary_gland)
What are some symptoms of depression?
- difficulty concentrating, remembering details, and making decisions
- fatigue and decreased energy ***metabolism & Thyroid gland function & circadian cycles & weight & hunger
- feelings of guilt, worthlessness, and/or helplessness ***Sleep
- feelings of hopelessness and/or pessimism
- insomnia, early-morning wakefulness, or excessive sleeping ***Sleep & circadian cycles
- irritability, restlessness ***Sleep
- loss of interest in activities or hobbies once pleasurable, including sex ***Sex organ functions in both men
and women
- overeating or appetite loss
- persistent aches or pains, headaches, cramps, or digestive problems that do not ease even with treatment
***endorphin
- persistent sad, anxious, or "empty" feelings ***endorphin
- thoughts of suicide, suicide attempts ***endorphin
(http://www.webmd.com/depression/guide/detecting-depression)