Wow, what a comprehensive and useful article! Like a reference work on the interaction of prescription drugs, nutrients, exercise, acupuncture, stress, trauma and other things with the endocannabinoid system. That is, the receptors that THC fits into, and the native compounds in the human body that fit into those receptors. Surprise! The receptors that recreational drugs fit into have entirely different (and natural) uses. The endocannabinoid system is deeply involved with mood, sleep, "the extinction of aversive memories" (see link at bottom), the perception of pain, appetite of course, and a dozen other physiological processes. This paper is concerned mainly with things that upregulate the system, as the title says. That means to make it bigger (i.e. - more receptors, or more of the biochemicals that fit into the receptors, or both) or more active, or sensitive. You generally want your endocannabinoid system upregulated, to a degree. Some technobabble, but the layman can get through much of it without wondering what they're talking about. And, like I said, the info is useful.
Bookmarked for when I have two hours to really think about it as I read it. Thanks PLoS One!