CBD is well tolerated in humans with doses up to 600 mg not resulting in psychotic symptoms (15). In the few small placebo-controlled studies performed, no significant CNS effects were noted. Oral CBD undergoes extensive first-pass metabolism via CYP3A4, with a bioavailability of 6%. Following single doses in humans, the half-life of CBD when taken orally is about 1 to 2 days.1 In vitro studies have shown that CBD is a potent inhibitor of multiple CYP isozymes, including CYP 2C and CYP3A (16, 17). Whether these in vitro observations are relevant at plasma concentrations likely to be seen in patients is unclear. In addition, given its metabolism via CYP3A4, clinical trials of CBD in patients receiving enzyme-inducing AEDs, such as carbamazepine or phenytoin, will require detailed pharmacokinetic studies.
Unlike THC, CBD will not make you high. That said, this doesn’t mean CBD is not at all psychoactive, as many assert, says Jahan Marcu, PhD, director of experimental pharmacology and behavior at the International Research Center on Cannabis and Mental Health in New York City: “CBD does change cognition. It affects mood, which is why people take it for anxiety. And some find that it makes them more alert.”
Another field in which CBD is creating a buzz is in the area of mood disorders like anxiety and depression. Both conditions have been treated with a variety of medications, courtesy of Big Pharma, that have had varying levels of success. Again, the long list of side effects can be off-putting to someone who just wants to get through the day without the sweaty tension of anxiety or the gray haze of depression.
CBD was also found to disrupt the consolidation of generalized fear memories when administered immediately after the acquisition of such fear memory. Interestingly, the timing of the administration of CBD was vital as the results demonstrated that delayed administration of the CBD dose did not have the same effective result that immediate administration did.
Side effects of CBD include nausea, fatigue and irritability. CBD can increase the level in your blood of the blood thinner coumadin, and it can raise levels of certain other medications in your blood by the exact same mechanism that grapefruit juice does. A significant safety concern with CBD is that it is primarily marketed and sold as a supplement, not a medication. Currently, the FDA does not regulate the safety and purity of dietary supplements. So you cannot know for sure that the product you buy has active ingredients at the dose listed on the label. In addition, the product may contain other (unknown) elements. We also don’t know the most effective therapeutic dose of CBD for any particular medical condition.