As someone who regularly takes a low dose of amphetamines (10mg IR) twice a day, I've developed a great interest in reading more scientific studies concerning dosage, evolution of dosage, and the effects of taking days off.

Might anyone point me in the direction of scientific articles addressing some of the following:

– How do psychiatrist identify optimal patient dosage / determine whether IR or XR is optimal?
– Can amphetamine be taken at the same dose for years on end and still maintain its effects?
– Is there any benefit to taking a day off per week? Likewise, is there any disadvantage physiologically in taking no days off?
– How can patients identify optimal dosage?

Any and all links to articles, studies, pharmacological or psychiatric, would be most appreciated.