Updated on Oct. 23 5:14 p.m. ET
Vape pens are easy to conceal, they're easy to confuse with other electronic gadgets like USB flash drives, and they generally don't leave lingering smells on clothes. All these things make them appealing to underage users, and confounding to parents. Gone are the days when sniffing a teenager's jacket or gym bag counted as passive drug screening. Now if parents want to know if their teens are vaping nicotine or cannabis, their best bet is a good old fashioned conversation.