INTRODUCTION
Methylxanthine (MTX) consumption is one of the most common customs in the world, occurring in most every society and culture (James, 1991; Barone and Roberts, 1996). Methylxanthines, which include caffeine, theophylline, and theobromine, can be found in a variety of different…
healthy you 
Although caffeine does not produce a clearly defined effect on mood, positive findings of significant mood effects are more numerous than negative findings.
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