There is a personality questionnaire called the "Temperament and Character Inventory" which purports to partition personality into a few dimensions of temperament some of which (supposedly) emerge from the independent neurotransmitter systems of the brain. [1] So basically if you trust the test you could use it to gauge your dopaminergic and serotonergic activity level (among other things). I've not researched the test enough to draw my own conclusions about it. Thus I can't say this it is a "good" way to measure anything in particular. I've not taken the test yet as I am loathe to sit through 240 questions only to find out things I already know. But I probably will at some point. You can take it online for $14.50 though a website somehow associated with its designer C. Robert Cloninger, M.D. [2]

[1] http://en.wikipedia.org/wiki/Temperament_and_Character_Inven...

[2] http://www.anthropediafoundation.org/site/PageServer?pagenam...