A method of increasing the cannabinoid levels in a genetically modified Cannabis sativa plant includes genetically modifying the plant to induce the overexpression of the gene that controls the expression of tetrahydrocannabinolic acid (THCA) synthase and/or cannabidiolic acid (CBDA) synthase. The overexpression of THCA synthase and CBDA synthase catalyzes an increased synthesis of cannabigerolic acid to tetrahydrocannabinolic acid and cannabidiolic acid, as well as the cannabinoids (3aR)-2,4,4-trimethyl-7-pentyl-3,3a,4,9b-tetrahydrocyclopenta[c]chromen-9-ol and 2-((1R,5R)-3-methyl-5-(prop-1-en-2-yl)cyclopent-2-en-1-yl)-5-pentylbenzene-1,3-diol. Pharmaceutical compositions comprising the modified cannabinoids produced by the transgenic Cannabis sativa plant or prepared synthetically are used to treat various diseases and conditions.