Absolutely a link! Lexapro actually worked better for my ADD symptoms than stimulant medicine, but over time, the Lexapro seemed to take the "life" out of me and paradoxically, left me feeling depressed.
It "slowed me down" so the ADD symptoms disappeared but the slowing down process was not good for my psyche.
The stimulants agree with me more, but to answer your question, ig you notice ADD sympotms lessening, it is defintely due to the Lexapro.