Feb. 1--IN NORTHERN STATES -- Minnesota, for example, or Alaska -- the shortened days and heavy skies of winter can lead to severe depression as part of seasonal affective disorder.

And while it's true that New Mexico gets much more winter sun than those areas -- clouds block only about 24 percent of available sunshine annually, according to the National Weather Service -- we still see seasonal changes.

Even here, according to local psychiatric and medical professionals, extremely susceptible people aren't immune to the disorder, though their depression can be eased with the same drug and light therapies used elsewhere.

The disorder, also known as SAD, is one of a small handful of conditions scientists believe is caused by a lack of sun exposure.

Unlike vitamin D deficiency, however, which is linked to a lack of enough sun exposure on the skin, researchers think SAD stems from insufficient light being absorbed by the eyes, says Dr. Jan Fawcett, a professor of psychiatry at the University of New Mexico. Exactly why is unclear, but Fawcett says something about the way light interacts with the eye prompts a chemical response in the brain that mimics traditional depression, altering levels of chemicals like melatonin and seratonin.

Fawcett says it's also unclear whether the disorder is caused by too many clouds blotting out the sun or by shorter days, though he believes it's both.

The trigger for the chemical changes might be similar to the triggers causing bears and other animals to hibernate in winter, he says. "There's a definite biological factor there."

While winter happens for everyone, he says, some people are more at risk for SAD than others.

Most at risk are those who live farthest from the equator in places like Scandinavia, where clouds are more common and the sun seems to disappear in winter months.

In places like New Mexico, those most susceptible are people with a history of depression or bipolar disorder. They might also have close family members who suffer from SAD.

It isn't common here, says Dr. Roderick McVeety, medical director of urgent care at ABQ Health Partners, but it's not unheard of. He says many patients come through his doors seeking treatment for SAD, often because they can't schedule an appointment with their general practitioner or they're seeking treatment for another ailment.

McVeety, who previously worked as a general practitioner in South Dakota, says it is much more common there.

Different from depression

Though some people are extremely susceptible, SAD doesn't necessarily pack a big punch, Fawcett says, especially in New Mexico.

"You're dealing with a spectrum here," he says. "Some people have severe manifestations and others mild."

In difficult cases, the disorder can cause clinical depression. Fawcett says a patient with clinical depression will constantly feel at least three of the following symptoms for two weeks: lack of energy; hopeless or suicidal thoughts; poor concentration; sleeping too much or too little; drastic changes in appetite; slowness in movement or speech; inappropriate guilt; or inability to enjoy what they've previously enjoyed.

While traditional depression can include both over- and under-sleeping, patients with SAD usually sleep more, says Albuquerque psychiatrist Dr. Judy McCarver. And, she says, while traditional depression can lead to periods of noticeable loss of appetite and weight loss, SAD typically brings about increased appetite and weight gain.

McVeety says clinicalgrade depression resulting from the disorder is less common in his Albuquerque experience than the tamer versions, something he terms "winter blues." A lot of patients, he says, only realize they have the winter blues when they feel the longer days lightening their moods.

"As spring starts to come, you get that spring fever," he says. "You get that jolt of feeling better."

Winter blues, he says, are easy to handle if sufferers merely change the routines that keep them away from what sun there is. For example, he encourages taking periodic breaks from office work to be outside for a bit.

"New Mexico is a wonderful place to change that behavior," he says. "Take advantage of it."

But if small alterations of daily habits don't improve mood, people feeling the effects of seasonal changes should seek professional help.

"You don't have to be really sad to have this," McVeety says, "it's not wrong or bad to be sensitive to the seasonal changes."

Easing the suffering

Treatment for SAD varies by patient, Fawcett says, including any combination of psychotherapy, antidepressant drugs or light therapy.

Jonathan Hart, a clinical psychologist in Albuquerque, says he doesn't encounter many clients with SAD, but that sufferers can learn to relieve themselves of the disorder's negative thoughts within 10 to 15 sessions of therapy.

Before starting therapy, though, Hart says he advises clients to address the physical sources of the disorder. He says the best place to do that is with a psychiatrist, who can prescribe the right drugs and point to a good source of light therapy.

A responsible psychiatrist will find the cause of depression, McCarver says, which could have physiological causes such as medication side effects, endocrine disorders like hypothyroidism and blood disorders like anemia. She says she would treat a case of SAD with antidepressants that will work without increasing appetite, such as Wellbutrin.

McCarver, McVeety and Fawcett say light therapy, using lamps that simulate the sun without emitting harmful ultraviolet rays, requires the guidance of a psychiatrist and consistent use to be effective. The devices can be found online, commonly costing $150 to $200, and they aren't covered by most insurance plans.

Used correctly, light therapy's results can be dramatic, McCarver says.

"It's very effective," she says. "As effective as Prozac."

Still, many patients opt for antidepressants without light therapy, less because the devices are expensive than because the light therapy requires about an hour of patients' time every day.

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