The effects and results of etiolation are not immediate. It would be like putting a human in an environment with less oxygen then we breath normally. Eventually you would see some very serious symptoms. Since air travels indoors we are fine but light is severely filtered through a window. UV rays do not penetrate windows which I believe is a strong factor in determining how well the plant does.
But even with 2 20watt bulbs and a south facing window this is not enough light. I have experimented with growing VFTs indoors. Even with 4 40W T8s the VFTs eventually went downhill. At first they flourished and were bright red, heck they even flowered, but you cant substitute pure sunlight. They grow in full sun out in the wild, not under bulbs so they can take a 'sunburn' if you will. They also can take low humidity, my RH was down to 25% this winter and they grew without a hitch indoors, until they said enough is enough.
If you still dont think that sunlight is a necessity do the experiment as I suggested, that way you wont have all your eggs in one basket when they go under.
As Jason stated if you have a place outside put them there but what you can do even if you are in an apt is put them in a hanging flower bed that hooks to your window.