NSAIDs interact with the endocannabinoid system and its endocannabinoids, as COX2 have been shown to utilize endocannabinoids as substrates, and may have a key role in both the therapeutic and adverse effects of NSAIDs, as well as in NSAIDs-induced placebo responses.
Definition: An independent variable is the variable that is changed or controlled in a scientific experiment. Independent variables are the variables that the experimenter changes to test their dependent variable.
Science is a way to understand our world and universe through repeated reliable observations and hypothesis development and testing. The observations must be repeatable by others besides the originator. From this, we conclude that nature is independent of a single observer or set of observers.