There's absolutely nothing new about the drop in daylight hours during winter months, but researchers in the later half of the 20th century managed to find, name and diagnose a condition related to it: seasonal affective disorder or SAD.
Like many suffering pathologies that are extremes of normal feelings, sufferers of SAD often face explaining why their "cabin fever" or "wintertime blues" is different.
According to the Mayo Clinic, SAD is a type of depression that can seriously affect someone's life. Sufferers of SAD show signs of hopelessness, anxiety, depression, oversleeping and difficulty concentrating. SAD sufferers may also crave food, particularly starchy or sugary food.
Since researchers noted the cause may be a lack of sunlight, it was quite easy to come up with a treatment: light therapy. According to the Mayo Clinic, people afflicted with SAD may find some relief in a special form of light therapy after a consultation with a mental health therapist.
Much like chronic fatigue syndrome, fibromyalgia is a condition associated with a myriad symptoms that once confounded doctors.
People with fibromyalgia feel fatigue, muscle pain at specific "tender points," headaches, insomnia, morning stiffness and memory problems.
"I think one of the reasons why people have skepticism about it, is because it's been very hard to pinpoint what causes it," said Dr. Roger Chou, an associate professor of medicine at Oregon Health and Science University in Portland.
Chou said the term fibromyalgia was coined in the 1970s. Ever since, doctors have theorized that the condition may be caused by a single underlying infection, as is the case in Lyme disease, or by an autoimmune disorder or a muscle disorder.
"None of that stuff has panned out," Chou said.
Although pharmaceutical companies have recently marketed treatments for fibromyalgia, Chou said the medication only helps some pain symptoms.
"It can be a really devastating disease," Chou said. "It can be so severe, that people can't get out of bed."
"Clinicians don't like to feel helpless, and we do feel like that with this condition," he said.
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