Hang on a second - how are they controlling for effective calorie intake? Intestinal bacteria steal calories, and I would expect that to affect activity level, especially in mice.

The inferential distance between this study and linking antibiotics to ADHD in humans is huge. It's the wrong species; a few antibiotics aren't at all like being raised in sealed plastic and fed autoclaved food (and as far as I know the few people that do live in hermetically sealed environments don't develop ADHD more often than normal); and for that matter, higher activity level isn't the same thing as ADHD. Neither the original study nor the Science Daily article mention antibiotics or ADHD. Sorry mom, there isn't anything here to even raise it as a possibility, let alone meet the elevated standard of evidence required for making reliable conclusions about human behavior.