How much adderall can a person safely take in one day?

I have been on Adderall for nine years and there really is no good answer to this question. The Physician's Desk Reference says 60 mg. per day is the maximum dose but that is not accurate. The problem is that from the first day you start taking Adderall, your brain begins the process of developing a tolerance to it. It does this by increasing the number of receptor sites on the post-synaptic side of the neural junction. As one's tolerance to Adderall increases, one needs a higher and higher dose to produce the same effects. Some people have gone to 120 mg. and even 200 mg. a day to obtain the same effects as when they started at 10 or 20 mg. per day. There are two major problems created as you keep increasing the dose of Adderall. First, the risk of significant cardiovascular consequences increases. Second, the more Adderall you take during the day, the lower you sink at night when the Adderall wears off and your body actually starts the beginning of withdrawal. At night you sink below what would be your normal mental levels. Therefore, in the morning, it will take longer for the Adderall to bring you to a satisfactory performance level because it has to take you from the valley it brought you into at night, to your normal performance level, and than to a satisfactory performance level. In short, the higher the dose, the deeper is the valley at night; the deeper the valley, the longer it will take in the morning it will take before a satisfactory performance level is reached.