And there's great individual differences in the efficacy of an individual therapist.

个别治疗师的功效存在很大的个体差异。

I think there are huge individual differences, but we know of studies where it appears that maybe 20 minutes of daily dosage of strong light is enough.

我认为这其中存在着巨大的个体差异，但我们知道一些研究表明，每天接受20分钟的强光照射就足够了。