Since starting Vyvanse I've lost 5.5 pounds over the last 3.5 weeks. Not a huge amount and basically because I'm eating healthier and avoiding candy bars and ice cream - plus exercising more. 8 pounds is typically what I fluctuate through the year.

Somehow though, I seem to FEEL thinner than when I was this weight last year. I swear clothes are fitting better too. Honestly, the way I feel about my weight right now, I'd think I lost 10#.
Is that possible? or could it be that Vyvanse puts me in a better frame of mind?

Hmmm ... I could be wrong but Body Dismorphia is usually a bad thing.

ie you've lost weight and think you've gained or have no sense of how thin you are ...still seeing a 'fat person' in the mirror when you're not ... or in men that are muscular and still believe they're too skinny or small.

In any case it seems that you're feeling good about yourself, which is fabulous!

I saw your post in the general ADD section as well and, although it's not what you were getting at, it is probably true that you've changed your body composition through exercise & diet ... weight can be extremely deceiving.

I've weighed 10 pounds more than a friend but 2 sizes smaller ...

I don't know about your medication as I've never taken it but I'd guess it's a combination of everything ... enjoy the positive benefits ;)