The possible benefits of cannabis in ALS are an important area of current research. Here is a link to a good review: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5270417/?report=classic. Cannabis contains many cannabinoids besides THC and CBD, and I would favor whole plant preparations over extracts as extracts may not contain important constituents active in the context of ALS. I would use a strain or combination of strains rich in both THC and CBD. While reduction of symptoms such as spasticity is one benefit to be sought, considering the lack of toxicity associated with cannabis the possibility of it having "neuroprotective" effects in ALS would warrant considering regular intake of medicinal cannabis. I strongly recommend discussing this with your neurologist.
drelkind