Was it a Sativa or Indica. 

There are many complex cannabinoids in different strains of Cannabis. 

Some who were taking the epilepsy oil were from a different type of Cannabinoid.

Also, the method of ingestion, for example, smoking versus eating, might affect hypertension.

Also, what were the total comparative health outcomes to non-users in a equivalent sample set, to draw a conclusion about health efficacy of Cannabis.