GreenDog18 - 4:15 am on Nov 9, 2012 (gmt 0)

Adsense in itself won't likely cause a drop in SERPS.

Now Adsense might cause poor user experience and a lot of users may bounce back to SERPS quickly signaling to the PANDA monster that your site is of low quality.

Provide good content and don't over do it with the ads and you should be good.