Ciaccio and Chan find that ADHD may be traced back to cigarette smoking by the maternal grandmother.

The Science Jerks News is hosted by Robert Chan (@999rpms) and Dave Ciaccio (@daveciaccio). Follow us on twitter @TheScienceJerks. Check out our weekly podcast, 'The Science Jerks', on iTunes, Stitcher or at TheScienceJerks.com.