For the study, 57 men took either CBD oil or a placebo (sugar pill) before a public-speaking event. The researchers based anxiety levels on measures like blood pressure and heart rate. They also used a fairly reliable test for mood states called the Visual Analog Mood Scale (VAMS).
There aren't many study trials that look at CBD's anxiety-relieving effects in humans. One of the few is a 2019 study published in the Brazilian Journal of Psychiatry.
This article goes over what CBD is used for, possible side effects, and what you should look for if you choose to buy CBD.
High Blood Pressure
Scientists believe CBD reduces nerve pain by binding to receptors in the brain that control the speed at which nerve signals pass between nerve cells.
No effect was reported in the studies included in this review for the treatment of Crohn’s disease, ulcerative colitis and type 2 diabetes with doses ranging between 20 and 250 mg/day for a treatment duration of 8 – 13 weeks [38-40]. While positive results were reported on seizure improvement with doses ranging from 350 to 2,000 mg/day and on the quality of life for patients with ADRs following HPV vaccine, with doses ranging from 25 to 150 mg/day, after 12 weeks of treatment [31, 33]. No definitive conclusion can be made on doses required for a positive effect since this may depend on the outcome assessed and study population.
In addition to its good safety profile and the lack of psychoactive effects, CBD presents also a wide range of therapeutic effects . Possibly for these reasons, CBD is currently one of the most studied cannabinoids . Several experimental in vitro and in vivo studies have shown that CBD has a broad range of therapeutic applications, displaying anti-inflammatory and immunomodulatory properties , anti-psychotic , analgesic  and anti-epileptic  effects, among others. Compared to Δ9-THC, CBD shows low affinity for cannabinoid receptor type 1 (CB1) and type 2 (CB2) . CB1 receptors are mainly found in the terminals of central and peripheral neurons and CB2 receptors mainly in immune cells . Several in vitro studies have shown that CBD, at low concentrations, has weak CB1 and CB2 antagonistic effect . It has also been reported that it behaves as a negative allosteric modulator of CB1, meaning that CBD does not activate the receptor directly but alter the potency and efficacy of orthosteric ligands of this receptor: Δ9-THC and 2-arachidonoylglycerol (2-AG) . These preliminary results need further validation, but may explain the ability of CBD to antagonize some of the effects of Δ9-THC reported in in vitro, in vivo and clinical human studies . It has also been suggested that the role of CBD as an allosteric modulator of CB1 can explain its therapeutic role in the treatment of central and peripheral nervous system disorders . CBD has also shown to have a strong inhibition effect of neutrophil chemotaxis and proliferation. In addition, it may induce stimulation of arachidonic acid release, reducing prostaglandin E2 (PGE2), and nitric oxide (NO) production. Furthermore, CBD reduces the expression of specific interleukins (IL-12 while increasing that of IL-10) by macrophages, and decreases the production and release of pro-inflammatory cytokines, such as IL-1, IL-6 and interferon gamma (IFNγ) from lipopolysaccharide (LPS)-activated microglial cells . The role of CBD as an inverse agonist of CB2 receptor may explain its known anti-inflammatory effects but this needs further investigation. There is also evidence of an antagonistic effect of CBD at the novel cannabinoid receptor G protein-coupled receptor 55 (GPR55), emerging from in vitro and in vivo studies. GPR55 has a role in bone physiology via regulating osteoclast function, formation and ultimately bone mass. CBD may affect the endocannabinoid system also indirectly, for example CBD can affect the endocannabinoid tone by increasing availability of anandamide; one possible mechanism is by inhibition of fatty acid amide hydrolase (FAAH), the enzyme that hydrolyzes the endocannabinoid anandamide .
RCTs are needed to confirm the effect of CBD on skin disorders, epilepsy and ADR following HPV vaccine. In addition, large and robust RTCs are needed to confirm the effects of CBD particularly on anxiety and psychosis. Studies should adhere to reporting standards for trials and use similar outcomes, standard measurements/tools to assess outcomes, and comparable treatment regimens to allow comparisons in future review studies. International guidelines should be implemented before the justification of further trials.
Among the randomized trials, three were judged at low risk of bias, eight were judged at high risk of bias and nine at uncertain risk. Major potential sources of bias were frequent in the following domains: randomization process and selection of the reported results. Most studies reported were randomized and double-blinded but few reported methods of randomization or participants and outcome assessor blinding. Selective outcome reporting was also a potential source of bias, since some studies did not report data for all outcomes specified in the methods section or trial register or changed the primary outcome from what was specified in the trial register.
Non-controlled intervention studies
This systematic review assessed the dosage schemes, effects and safety issues associated with the use of CBD. We included 20 RCTs, two non-RCTs and three observational studies for all indications of CBD use. In summary, 20 RCTs evaluated efficacy of CBD-use for schizophrenia, anxiety, Crohn’s disease, ulcerative colitis, dyslipidemia, nicotine addiction and cannabis use disorder. Most of these studies reported positive effect of CBD on anxiety, schizophrenia, tobacco addiction and minor effects or no effect on primary outcome measures for Crohn’s disease, ulcerative colitis, dyslipidemia and cannabis use disorder. All observational studies (skin disorders, ADR following HPV vaccine and epilepsy) reported positive effect of CBD when compared to baseline measures.
PRISMA flow diagram of literature search and selection process. PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-Analyses.
We identified 362 studies of which 85 were assessed for full-text eligibility ( Fig. 1 ). Finally, 25 studies were included: 22 controlled clinical trials and three non-controlled (single arm) trials [10-34]. Among controlled clinical trials, two were non-RCTs and 20 RCTs (14 individually randomized parallel group trial, five individually randomized cross-over trials and one cluster randomized cross-over trial). Studies were conducted in five countries with the majority of studies being conducted in the UK. All studies were reported in full length journal articles. The administration of CBD varied from single doses to chronic administration, up to 48 weeks. The pure form of CBD was used in the majority of the studies except for two studies using seed CBD oil and CBD-rich botanical extracts. The most common form of drug administration was in the form of oral capsules, and other forms were vaporization and sublingual oil. The most common comparator was placebo only one study used an active-control group. Results for controlled clinical trials and non-controlled studies are presented in Table 1 [17-37] and Table 2 [38-40], providing a summary of the included studies and their principal findings.
In all studies, expect for one that used plant extracts , purified CBD was administered. Data derived from pre-clinical animal models indicate that purified CBD may have a bell shape response  which was also confirmed in two studies included in this review [25, 26]. It is likely that the use of a single cannabinoid may be inferior to the extract where other components synergize with CBD to obtain the desired effect, known as the “entourage effect” . Further, the main route of administration for the studies included in this review was oral (either in the form of capsules or sublingual oil). Animal studies suggest that oral bioavailability is low ; on the other hand, as highlighted in a recent systematic review on the pharmacokinetics of the CBD in humans , there is a lack of data in humans .
We extracted the following data: condition and symptoms, year of publication, country, study population, number of patients, age, gender, weight, outcome measures, effect of treatment, side effects, dosage, administration form (pills, smoking, oil, etc.), length of treatment, doses, product/brand, isolated CBD or full spectrum and funding/sponsors.