What Can CBD Do for You?
This novel cannabinoid offers promise for some health disorders.
Posted August 28, 2025 | Reviewed by Michelle Quirk
Cannabidiol (CBD) acts very differently from tetrahydrocannabinol (THC); it’s non-psychoactive and not intoxicating, and it does not induce abuse or dependence. It’s highly fat-soluble; thus, it enters the brain easily. However, it has low solubility and absorption in water, which produces variable pharmacokinetics and contributes to the difficulty in studying its multiple mechanisms of action. Bioavailability via inhalation averages about 31 percent, while oral bioavailability is only about 6 percent in humans. Therefore, don’t bother eating it.
Most (about 72 percent) CBD users are between 25 and 54 years of age and male. In surveys, the most mentioned reasons for CBD use were anxiety (42.6 percent), sleep problems (42.5 percent), stress (37 percent), and general health and well-being (37 percent). Older users usually turn to CBD for pain relief. CBD directly interacts with numerous receptors targeting multiple pathways and mechanisms of action; all of these may contribute to the therapeutic benefits listed below.
Inflammation and pain
Preclinical studies in animals have provided some useful insights and mechanisms. For example, CBD stimulates the TRPV1 receptor. This receptor allows the brain to experience the painful sensation of eating hot chili peppers and wasabi. CBD’s actions desensitize this receptor, resulting in analgesia or pain relief, especially for neuropathic and inflammatory pain. CBD might also inhibit voltage-gated sodium channels, like lidocaine; this would also contribute to the reduction in the sensation of pain. CBD can reduce localized neuroinflammation-related pain by stimulating the transcription factor PPARγ. Finally, CBD stimulates a specific receptor for serotonin, 5-HT1A, which would reduce oxidative stress and inflammation and have the bonus of reducing anxiety associated with the pain.
In contrast to these promising results from animal studies, clinical studies in humans with chronic pain remain unimpressive and inconclusive. The problem is that most clinical studies utilized a mixture of THC and CBD. Studies evaluating the isolated effect of CBD are rather scarce and unconvincing. The clinical benefits of a mixture of CBD and THC likely resulted from the presence of low levels of THC. However, some recent small studies have reported that the transdermal application of CBD oil can produce significant reductions in pain in patients with peripheral neuropathy. Overall, the effectiveness of CBD for pain relief remains to be proven conclusively.
Imaging studies in humans
Magnetic resonance imaging (MRI) studies have shown that CBD changes the nature of the brain’s overall activity. CBD reduced resting-state activity and connectivity across several brain regions, which the authors interpreted as a potential explanation of its anxiety-reducing effect. A positron emission tomography (PET) study investigated the effects of CBD in the brains of people at high risk of psychosis . CBD produced changes in brain function in regions that are involved in the development of psychosis. Specifically, the CBD treatment was associated with improvements in cognitive performance and reduced symptoms of psychosis, suggesting that CBD may have potential as a treatment for people at high risk of developing psychosis. These benefits might be related to the ability of CBD to antagonize the actions of endocannabinoids in the brain.
Neurological disorders
CBD consistently shows benefits in animal models of Alzheimer’s disease, Huntington’s disease, and Parkinson’s disease; however, clinical studies in human subjects have never confirmed any of these benefits. The problem is that the current animal models are not valid representations of the biological conditions associated with these disorders.
CBD may reduce psychotic symptoms by indirectly increasing the levels of the endogenous cannabinoid anandamide. CBD (800 mg/d) given to acutely schizophrenic patients reduced some psychotic symptoms. In one female schizophrenia patient who could not tolerate standard treatment, a high dose of CBD (1500 mg/d for 26 days) produced significant improvements in psychiatric symptoms without any side effects. Additional trials have determined that these higher doses (800 or 1000 mg/d) are required to effectively treat psychotic symptoms, although some treatment-resistant schizophrenics did not respond to a CBD dose of 1280 mg/d.
Anxiety and depression
Human clinical trials have documented the anxiolytic effects of CBD. Three hundred milligrams of CBD reduced anxiety induced by the simulated public speaking test. Six hundred milligrams significantly reduced the symptoms of patients suffering from social anxiety disorder. The dose is relevant for CBD, which presents with an inverted U-shape in which intermediate doses are effective while low and high doses are not. These discoveries have led to the use of CBD for the treatment of phobias and posttraumatic stress disorder. The antidepressant -like effects of CBD have been shown in some, but not all, animal models. No reliable clinical studies have investigated the effect of CBD on depression in humans.
CBD has been suggested as a therapeutic approach to improve sleep, mostly based on hypotheses about its mechanisms of action in the brain. Despite these theories, CBD has no effect on sleep quality and quantity in subjects with an undisturbed and healthy sleep pattern. CBD might offer benefit to those suffering from insomnia due to anxiety. Clinical studies also report that CBD causes an increased wakefulness and reduces REM periods during sleep. The current evidence does not support using CBD to achieve normal restful sleep.
The current evidence remains limited. There have been too few human studies, the sample sizes have been small, the CBD doses varied too much, and control groups were often lacking. One major example is the management of chronic pain. CBD users often report pain reduction that cannot be scientifically proven. The problem is that the experience of pain is highly vulnerable to the placebo effect . Overall, the evidence for treating anxiety and anxiety-induced insomnia is more convincing. Future studies will need to discover why preclinical trials in animals consistently show the benefits of CBD while clinical trials in humans do not.
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Gary L. Wenk, Ph.D. , is a professor of psychology, neuroscience, molecular virology, immunology and medical genetics at the Ohio State University.
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This article is part of the Bringwise Psychology Journal — daily insights on human behavior, mental health, and personal growth.