A reader asks:

How long should you be treated with an artificial sunlight bulb?


We do not recommend treatment with “bulbs” per se, but rather with light therapy systems that include a wide spread of diffuse illumination of appropriate intensity directed at an angle from above the line of sight. Furthermore, we do not recommend use of bulbs designed to mimic sunlight, because they can emit ultraviolet radiation with an intense blue component in the white, neither of which is necessary or conducive to the treatment. For an example of the type of system that is optimum for light therapy, check out http://www.cet.org/store. As for the timing of treatment, this is a highly individual matter. The same website also offers general guidance using the Automated Morningness-Eveningness Questionnaire, but adjustments under clinical supervision may be necessary.