The darkest days of winter are here. Happy lights might help.

Treatments for seasonal affective disorder, or SAD, are a lot like treatments for other types of depression, according to Lisa Lindquist, chair of psychiatry at Providence Alaska Medical Center, with one notable exception: light therapy.

Using a light box every morning can help with SAD symptoms. Light therapy has even been shown to prevent the onset of SAD for some people who have experienced it in the past, Lindquist said.

The internet is replete with options to buy lights marketing themselves as treatment for SAD. But Lindquist cautioned that there are a few things buyers should look for when purchasing a light.

First, the light’s lux —meaning the intensity of the light — must measure at 10,000 lux when it is 14 to 30 inches from a user’s eyes. Also, the light should filter out UV rays, which can be harmful.

Joe Vergnetti, pharmacy technician at Lake Otis Medical Supply in Anchorage, said he sells about 50 light boxes a year. People start to ask about the boxes in the fall, he said, and the store sells them throughout the winter.

The store’s most popular model is a rectangular light box that can sit on desks or tables.

"People are just in the doldrums,” Vergnetti said.

Related: Feeling SAD? Seasonal affective disorder rears its yearly head in Alaska.]

Lindquist tells her patients to switch on their light as soon as they wake up and keep it on for about 20 minutes. From there, over time, it’s possible to work up to an hour per day.

Jennifer Thorsteinson of Juneau said she had used a light therapy box before but lost it during a move. She drove around Juneau, stopping at Costco, Fred Meyer, Home Depot and a few pharmacies looking for a light box, but to no avail. She couldn’t find a lamp anywhere and instead ordered one on Amazon.

Thorsteinson said she props the light up on her desk at work in the morning. It’s about the size of a standard iPad and emits 10,000 lux. She takes it home on the weekends and uses it while she’s doing the dishes or making coffee.

If you or someone you know is experiencing thoughts of suicide, call the National Suicide Lifeline at 1-800-273-8255, or the Alaska Care Line AT 1-877-266-4357.