CBD for Anxiety: Does It Work? Evidence and Doses

Short answer

The evidence is mixed and thin. A few small human trials found that CBD lowered anxiety in one specific setting, such as public speaking. Other trials found no difference from placebo. The FDA has not approved CBD for any anxiety disorder. The only prescription CBD drug, Epidiolex, is approved for two rare forms of epilepsy, not for anxiety.

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What CBD is

Cannabidiol is one of more than 100 cannabinoids in cannabis. At common doses it does not produce a high. It has low affinity for CB1 and CB2 receptors and acts on other targets, including serotonin 5-HT1A receptors and TRPV1 channels. Those targets are the reason researchers study it for anxiety.

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What the trials show

• 2011 trial, 24 people with social anxiety disorder: 600 mg CBD before a public speaking test reduced anxiety compared with placebo.
• 2019 trial, 37 people with public speaking anxiety: 300 mg CBD showed no difference from placebo.
• Reviews from 2015 and 2019 found mostly lab studies and small trials. Sample sizes ran from 10 to 60 people. Most trials measured a single dose on a single day.

No large phase 3 trial has tested CBD for generalized anxiety disorder or panic disorder. Long-term daily use is not well studied.

cbd for anxiety does it work

Doses used in studies

Human trials used 150 mg to 600 mg in one dose. Epidiolex doses run higher, at 10 mg/kg to 20 mg/kg per day for epilepsy patients. Over-the-counter CBD labels often do not match the contents. A 2017 study in JAMA tested 84 CBD products sold online: 26% contained less CBD than the label stated, and 43% contained more.

Side effects and interactions

Reported effects include drowsiness, fatigue, diarrhea, and appetite changes. CBD inhibits cytochrome P450 enzymes. That can raise blood levels of warfarin, clobazam, and some antiseizure drugs. Liver enzyme increases occurred in patients who took high daily doses. Ask a pharmacist before mixing CBD with prescription drugs.

Legal status in the US

Hemp-derived CBD with less than 0.3% THC is legal under federal law. State rules differ. Some states limit sales to licensed dispensaries. The FDA has not set rules for CBD in food or dietary supplements.

What to ask a clinician

1. Does a CBD product interact with my current prescriptions?
2. Is a treatment with published evidence, such as CBT or an SSRI, a better first step?
3. What dose and duration would be tracked, and how?

Open questions remain: long-term effects, the best dose, and how CBD compares with standard anxiety treatments. No trial has answered those.