Daily use of a lightbox that produces very bright artificial light is the optimal way to reverse the symptoms of seasonal depression. Therefore, you might be tempted to think that switching from conventional lighting to full spectrum or higher wattage lightbulbs at home or in the office would achieve the same benefits. Unfortunately, this is not the case, because without the use of special ballasts, bulbs and reflective surfaces it is not possible to generate light of sufficient intensity to do the job adequately or safely.
Almost all of the energy produced by conventional (incandescent) bulbs is in the form of heat, so that using them to generate very intense light is not only impractical - requiring numerous fixtures and high wattage - it can also be dangerous. Bulbs used in conventional ceiling lighting - whether fluorescent or incandescent - are generally several feet from the human eye and the light produced by them is cast downward rather than toward the eyes. Bulbs in table lamps or floor lamps may provide a light source closer to the eyes, but can cause excessive glare when directed toward the eyes.
A properly designed lightbox generates an intense but pleasant light at a comfortable distance; it is designed to deliver 10,000 lux (in contrast to standard room lighting, which rarely exceeds 500 lux) in a short period of time with complete safety, and without heat buildup. The special fluorescent tubes are powered by high output electronic ballasts, to eliminate headache-producing flicker; these ballasts cycle thousands of times per second, cycling which is imperceptible to the human eye. A lightbox generally needs to be used only 15 to 30 minutes per day, usually in the morning, to be fully effective for alleviating the symptoms of seasonal depression (lethargy, oversleeping, carbohydrate cravings, irritability) especially if treatment is begun when the symptoms start, usually mid-Autumn. It may require longer sessions of light treatment, and/or prescription antidepressants, to get some folks out of the doldrums if they wait until after Winter has begun to address the problem.
Light treatment is also used for insomnia, jet lag and problems adjusting to shift work, but professional consultation is strongly advised to determine the proper timing of light treatment for these problems.
In summary, although replacing lightbulbs at home or in the office with brighter or "full spectrum" bulbs often has desirable effects and may indeed increase the amount and quality of ambient lighting, it is not a substitute for using a lightbox to treat seasonal depression and related light-deprivation problems.