Amphetamines and habituation, dependence, tolerance, or abuse are all very important issues to talk over with your prescriber.
For what it's worth, methylphenidate (ritalin) causes less DA and NE release and tends to be less "rewarding". It may or may not be as effective; my impression is that d-amphetamine is a surprisingly good drug with little anxiety side effects. IOW, it is a stimulant, but it really doesn't cause anxiety. The d-isomer is primarily active in the brain (where as the l-isomer is active at the "Oh Crap I'm Scared Now" parts of the body, like the adrenal glands).
Medication-related posts are for brainstorming purposes only. Talk to your doctor.
My meds: Parnate, Lamictal, Wellbutrin, trazodone