Investigators at Italy’s University of Perugia, Department of Public Health, reported that patients with chronic migraines possessed "significantly lower" levels of the endogenous cannabinoids anandamide and 2-arachidonylglycerol (2-AG) in their platelets compared to age-matched controls.

"These data support the potential involvement of a dysfunctioning of the endocannabinoid and serotonergic systems in the pathology of chronic migraine and medication-overuse headaches," researchers’ concluded.

A previous paper published in the journal Neuroendocrinology Letters similarly suggested that migraine, fibromyalgia, and other treatment-resistant conditions may be associated with dysfunctions in the endocannabinoid system. This system is believed to play a primary role in regulating humans' mood, appetite, skeletal development, motor coordination, digestion, and reproduction.