By Rebecca Fenton, News Staff

For the 4 to 9 percent of Americans suffering from Seasonal Affective Disorder (SAD), winter may feel more like a time for hibernation than an opportunity to play in the snow.
Those who live with SAD experience depressive symptoms like body aches, loss of sex drive and fatigue, experts say. And since the disorder first gained recognition in 1985, it was accepted that increased distance away from the equator was the primary cause for SAD.
However, recent evidence points more toward genetics.
In a study published in November on ScienceDaily.com, an online publication that posts scientific research, scientists found that SAD may be a result of a genetic mutation. The discovery’ of the circadian rhythm regulating protein melanopsin is critical in differentiating SAD from the winter blues, which many claim to experience. Melanopsin is found in the retina, the light sensitive tissue lining the inner surface of the eye.
While SAD is most common during winter, doctors estimate that about one-tenth of SAD cases occur during the summer.
‘SAD is not a clinical diagnosis but a subtype of clinical depression,’ said Ignacio Provencio, a professor of biology at the University of Virginia in Charlottesville, who is credited with uncovering the recent link between melanopsin and SAD, along with his colleagues. Typically, those with SAD experience less anxiety than those with clinical depression, experts say.
Melanopsin is a photopigment in the eye that is involved with regulating the body’s natural internal clock and may help explain why people experience symptoms associated with SAD.
‘If individuals have two mutative copies of melanopsin, they are likely to have SAD,’ Provencio said. ‘This mutation may explain up to five percent of all cases for people in the US with [the disorder].’
Knowledge of this genetic composition and an ability to distinguish it from the more common winter blues could help those with SAD obtain proper treatment, Klein said.
John Speranza, a senior economics major, said he often experiences the winter blues, or a day-to-day type of lethargy, but his symptoms don’t lead him to believe he has SAD.
‘It’s gray and cloudy for a week and I’ll just want to sleep for a while,’ he said.
SAD is a discreet clinical syndrome that has a set of symptoms that go beyond feeling down during the winter, said Robert Klein, director of behavioral health at Northeastern University Health and Counseling Services.
While some may refer to the two interchangeably, Klein said SAD typically begins in October and subsides in May, as opposed to the more fleeting winter blues, which could last anywhere from a few days to two or three months.
‘I think living here in [Boston] it’s almost impossible to not have one of the two,’ Speranza said. ‘I have some depressive tendencies more so in the winter than the summer, but nothing I would seek medical care for, or that I feel I need a prescription to get over.’
Other students, who are used to warmer climates, add that New England’s winter weather can put a damper on going out.
‘Coming from a Florida school I was used to going out and enjoying the nice weather,’ said Sam Johnson, a middler criminal justice major who transferred from a college in Florida. He added that going out during the winter in New England can ‘sometimes feel like a hike.’
Like a watch that runs too quickly or slowly, people with SAD have internal clocks, or circadian rhythms, that are not correctly synchronized with the events of the day. Training the biological clock through a method known as light therapy proves to be the most effective treatment for SAD, Klein said.
This type of therapy works with the hormone melatonin, which is responsible for regulating circadian rhythms by chemically causing drowsiness. Symptoms of SAD can be affected by specialized blue-light treatment. This light therapy uses intense illumination to produce hormones and neurotransmitters that affect mood and overall well-being, Klein said.
‘Light treatments that treat SAD also have direct effects on melatonin levels,’ said Frederick Davis, professor and chair of’ Northeastern’s biology department. ‘While you are both maybe entraining rhythms better, you are probably also affecting the level of melatonin by the affects of light.’
Melatonin is an ambiguous hormone that researchers are still trying to figure out, Davis said.
Still, light therapy proves to be the most effective way to regulate circadian rhythms.
‘Light therapy is effective in at least 50 percent of patients who use it, and a 50 percent response rate to a therapy is impressive,’ Klein said.
While some doctors recommend treatments like anti-depressants coupled with psychotherapy, some people with SAD simply prefer to wait for spring.
‘If you don’t seek help be assured that when winter is over, you’ll be fine,’ said Laura McGann, secretary of the biology department who said she has symptoms of SAD,’ although she has never been clinically diagnosed.
‘The worst it has ever affected me was this past winter when I considered talking to somebody about being depressed,’ said McGann, who said her mother was diagnosed by doctors with SAD. ‘You get yourself into a funk and it’s hard to think beyond what may be causing it.’