Dr. Daniel McCartney:

I can take that. There are certainly lamps for SAD. These use white light at specific wavelengths which are higher than those of the ultraviolet B, UVB, radiation associated with vitamin D. Even though there is a crossover between SAD and the depression associated with vitamin D deficiency, the remedy with regard to light therapy may be quite different. The UVB radiation to which one must be exposed to synthesise vitamin D has a wavelength of 290 nm to 315 nm whereas the white light associated with better outcomes in people with SAD is higher at about 400 nm. Does that answer the Deputy's question?