Amyotrophic Lateral Sclerosis, the Endocannabinoid System, and Exogenous Cannabinoids: Current State and Clinical Implications

A unifying mechanistic cause for amyotrophic lateral sclerosis (ALS) remains uncertain. Multiple pathophysiological processes appear to occur simultaneously. Cannabinoids, including delta-9-tetrahydrocannabinol (THC), cannabidiol (CBD), cannabigerol (CBG), and others found in cannabis, and cannabis extracts (CEs), appear to have activity in these pathogenic pathways, which have led to increasing interest in cannabinoids as therapeutic agents for ALS. The use of cannabinoids as a treatment strategy is substantiated by preclinical evidence suggesting a role for the endocannabinoid system (ECS) in ALS and other neurodegenerative disorders. Preclinical data indicate that cannabis and CEs have powerful antioxidative, anti-inflammatory, and neuroprotective effects in the SOD1 ^G93A mouse model of ALS. The use of CEs in SOD1 ^G93A murine models has been shown to prolong neuronal cell survival, which leads to delayed onset of the disease state, and slows progression of the disease. Although research in humans remains limited, a few studies suggest that cannabis and CBD, in humans, provide benefits for both motor symptoms, including rigidity, cramps, and fasciculations, and non-motor symptoms including sleep quality, pain, emotional state, quality of life, and depression. There remains a need for further, well-designed clinical trials to validate further the use of an individual cannabinoid, or a combination of cannabinoids, as a disease-modifying therapy for ALS.