A youthful lady with cat eye makeup and pink lips sat in front of Parks Library. Behind her stylish exterior, the woman hid an uncontrollable depression. 

Fabiana, not her real name to protect her identity, is a graduate student at Iowa State, and she suffers from seasonal affective disorder almost every year.

“My first episode with such depression was when I was 15 years old. And since then, I feel sad every winter,” she said.

Seasonal affective disorder, which is an annual episode of depression, is characterized by sorts of depressed feelings, craving for carbohydrates and an increased need for sleep that lasts from late fall and into wintertime.

The Student Counseling Center at Iowa State estimated that 20 percent of ISU students may suffer mild symptoms of SAD, including a downturn in mood when the weather turns gray. For 2 to 5 percent of the sufferers, symptoms can be crippling.  

With those estimations, about 5,722 ISU students suffer from mild seasonal affective disorder and about 574 to 1,430 students suffer from severe seasonal affective disorder. Epidemiological studies estimate that the adult population with SAD or “winter blues,” a milder form of SAD, ranges from only 1.4 percent (Florida) to 9.7 percent (New Hampshire).

“SAD is widely identified as being linked to shorter and shorter sunlight during the winter months, which leads to a longer duration of melatonin secretion than summer time,” said Jeffrey K. Ellens, licensed counselor at Student Counseling Service at Iowa State.

Melatonin, a hormone, which was identified in 1958 as the primary controller of circadian (day/night) bio-rhythm, is produced by the pineal gland, a small endocrine gland in the vertebrate of the brain. The pattern of wake-sleep depends on the real-time signal of an internal circadian clock, which works with photodetectors in the eyes to sense light and darkness. The melatonin secretion continues to increase in the onset of sleep and gradually diminishes toward dawn, reminding individuals to wake up in the morning.

A report published in 2001 in the Archives of General Psychiatry discussed an experiment at the National Institute of Mental Health conducted to examine the timing and amount of melatonin released in a 24-hour period circle. A total of 110 subjects participated in this experimental project. For the experiment, 55 subjects who had seasonal affective disorder and 55 who were healthy volunteers, who served as a control group, were arranged in a dimly lit lab.

The conductors measured blood levels of melatonin in plasma samples every 30 minutes for a 24-hour circle in each season. They found that the patients with seasonal affective depression had 38 minutes longer in the duration of nocturnal melatonin secretion during the winter compared to that secreted in the summer. However, there was no significant difference between healthy individuals in the summer and winter.

For treatments, there are mainly three types for all seasonal affective disorder sufferers: 1.) talk therapy, 2.) anti-depressant medications and 3.) bright light therapy. Large groups of mental health professionals and researchers believe bright light therapy is the most established treatment for the disorder. It aims to alter circadian rhythm of the human body, suppressing the body’s natural release of melatonin and causing a biochemical change in the brain.

During the bright light therapy, patients sit or work near a light therapy box, which gives off special light. This kind of light mimics the natural outdoor light of summer or spring. The intensity of the bright light box is recorded in lux, which is a measure of the amount of light you receive at a certain distance from the light source.

A light box for seasonal affective disorder treatment usually produces between 2,500 lux and 10,000 lux, while the intensity in an average living room is less than 400 lux. In fact, there is almost 100,000 lux produced on a bright, sunny day in the summer.

“Many patients show improvement by using the light box 30 minutes a day, best in the morning,” Ellens said.

Choosing the most suitable type of light box for various conditions is necessary, which could help individuals to avoid negative effects for their eyes. One regular light box can vary between $150 and $400.

The intensity of a light box could determine how far a patient sits from it and how long time a patient should be exposed to it. The 10,000 lux bright light box usually require 30 minutes sessions every day, while 2,500 lux bright box needs at least two hours of exposure time.