I've been taking Adderall (both XR and regular) for about a year now. I was on Provigil for narcolepsy/ sleep apnea. However, after I had surgery for the apnea, the provigil made me manic, and then I would crash and be exhausted. I switched to Adderall after realizing I had attention problems. I used the XR during the day, some days it worked better than others, but I usually felt it regardless. The regular I would use in the afternoon to keep myself up.

I think our bodies and minds become adjusted to the adderall and it becomes less effective. I think we just get used to how it makes us feel, so it just doesn't FEEL like it is working.