– In this Dec. 6, 2012, file photo, a person holds a freshly-rolled marijuana joint just after midnight at the Space Needle in Seattle. A new analysis released Monday, Jan. 18, 2016, is challenging the idea that smoking marijuana during adolescence can lead to declines in intelligence. Instead, the new study says, pot smoking may be merely a symptom of some other problem that is really responsible for a brainpower effect seen in some previous research. (AP Photo/Ted S. Warren, File)