I think it is possible that the individuals who don't get high are suffering from an endocannabinoid deficiency. The THC doesn't have a chance to reach their brains! All of their cells are hungry for endocannabinoids like anandamide (sp?) that our body is supposed to make. The THC is grabbed up by the millions of cells that it has to get by before getting to the brain. Once the other cells get fed, then the brain can get some. Here's an article about endocannabinoid deficiency. http://www.freedomtoexhale.com/clinical.pdf