Abstract: Administering a therapeutically effective dose of lithium ions mitigates the side effects of a psychoactive substance such as a cannabinoid. The therapeutically effective dose of lithium ions includes greater than 4 milligrams of lithium and less than 170 milligrams of lithium, or includes between 8 and 32 milligrams of lithium ions per milligram of the psychoactive substance. The therapeutically effective dose of lithium ions is administered using lithium carbonate, lithium citrate, lithium chloride, lithium orotate, lithium aspartate, or analogs thereof using a delivery vehicle selected from pills, tablets, capsules, gelcaps, liquids, syrups, injectable liquids, powders, or foods and administered prior to, with, or after administration of the psychoactive substance. The psychoactive substance includes one or more of anandamide, 2-arachidonoyl glycerol, 2-arachidonoyl glycerol ether, tetrahydrocannabinol, cannabinol, cannabidiol, or analogs thereof and may be administered using the delivery vehicle.