I have found that adding lights that give more UV light can be beneficial up to a point.
However, using lights specifically designed to emit exessive UV-B will confuse and even burn the plants. It can be done if you have warehouse ceilings so the UVB source is nowhere near the plant surface, but for most of us, MH and Fluorescents are the best way to get extra UV.
I use mostly HPS bulbs, with added MH and daylight spectrum fluorescents. I do find that the buds closer to the bluer lights develop more trichomes.