Certain xanthines, such as paraxanthine and theophylline, produce stimulant and behavioral effects comparable to caffeine while involving differing molecular pathways such as cGMP accumulation and phosphodiesterase inhibition.
The retrieved papers consistently support the claim that xanthines other than caffeine (such as paraxanthine and theophylline) provide stimulant and behavioral effects, and that these effects involve various chemical pathways including, but not limited to, adenosine receptor antagonism, nitric oxide signaling, and phosphodiesterase inhibition. Papers [1], [4], and [8] directly corroborate these multiple mechanisms and stimulant outcomes.