I live in Alaska which has months of darkness. The sun comes up while we are all at work and goes down before we get to leave work so if we don't sit by a window we never see daylight. Our office building has installed a full spectrum bulb in the flourescent fixtures above each seat in the building. This has helped a number of our employees who are affected.
I do not have SAD, but I have seen many who do, it can be quite debilitating for some.
My husband works on the North Slope at Prudoe Bay. The employees fly to work and live there for 2 or 3 weeks at a time (housekeeping works 4 weeks straight) The sun does not come up there for a couple months. It is night time all the time. Part of the hiring process is to take a class about the conditions. They learn about Circadian Rythms because it has a major impact on behavior. Google it. It is the behavioral process of living entities as determined by the daylight they receive. They learn how to manage, suppliment, distinguish and treat themselves while in the dark days to prevent SAD.
The full spectrum lights look like normal light. Install them in your bathroom light bar, your reading lamp, the light above the kitchen sink... anywhere you spend time near the light. They do help.
Good luck to you.
Michelle