Last updated 26 August 2026 · Originally published 18 July 2021
The CBD psychological effects most people want to know about are simple ones: will it get me high, will it make me foggy, will I feel anything at all? Pure CBD does not produce a THC-like high. At a typical retail serving, most people will not notice a clear effect on their thinking, although some report drowsiness, heaviness or fogginess. What CBD does to the mind at the much larger doses used in trials is a more interesting question, and this article covers both.
It does not get you high
CBD is not intoxicating, and this has been tested harder than most things about it. In a 2022 University of Sydney study, 17 healthy adults took a placebo, 15 mg, 300 mg or 1,500 mg of CBD on separate days and then did a driving simulator and a set of thinking tests. No dose produced feelings of intoxication or measurable impairment of thinking. The driving results were generally reassuring, although some comparisons were inconclusive. It was a small study of single doses in healthy adults, not proof that CBD can never affect driving. If CBD makes you sleepy or foggy, do not drive. Full spectrum products may also contain enough THC to impair driving or trigger a roadside test.
If a CBD product does make you feel high, the likely reason is THC or another undeclared intoxicating cannabinoid. Full spectrum products contain some, mislabelled products can contain a lot, and “THC-free” does not always mean what it says. That is a labelling problem, not a CBD effect.
What you feel at a retail serving
Measured, usually nothing you can put your finger on. In the Sydney study, 15 mg — a typical serving — was indistinguishable from placebo on every measure.
Reported, quite a lot. Ask people who take CBD regularly and the same descriptions come up over and over: calmer, less on edge, “takes the edge off”, easier to switch off at night, less inclined to ruminate. Some describe a mild heaviness or drowsiness, especially with larger servings or in the evening. A minority say it does nothing for them, and a few say it makes them feel flat, foggy or slightly nauseous. In a 2,409-person US survey and a 387-person, mostly UK survey, most people said they took CBD for anxiety, sleep or pain, and a clear majority said it helped at least somewhat. Remember, though, that the surveys recruited CBD users, who are unusually likely to have had a good experience. They show what consumers report, not how often CBD works in the general population.
The reports are worth recording because they show what consumers experience and what researchers should test. They do not establish that a subtle feeling at 20 mg is the same effect seen in a 300 mg trial. What the reports cannot do is separate the CBD from everything around it. A feeling of calm after a 20 mg gummy could come from the CBD, from expectation, from the ritual, from the time of day, from natural changes in anxiety, or from some combination of them. That is not a reason to dismiss what people report. It is a reason to hold two things at once: the experience is real, and its cause is not established.
What it does at trial doses
At several hundred milligrams, CBD is more active in the body, but the evidence depends on what is being measured.
Anxiety under stress. Several small studies found that single doses of 300 to 600 mg reduced anxiety during public-speaking tasks. The results are not fully consistent, most studies were small, and this does not establish CBD as a treatment for an anxiety disorder. Our anxiety article goes through them and their limits, and our serotonin article covers what is and is not known about why.
Sleepiness. At prescription epilepsy doses, drowsiness is common, particularly in people also taking clobazam. That is a real effect of CBD on the mind, but it does not make CBD a reliable sleep aid: a controlled insomnia trial using 150 mg found no improvement in insomnia severity, sleep onset or most other sleep outcomes, and other trials remain mixed. Our sleep article goes through them.
Psychosis. This is the most surprising one. Trials using 600 to 1,000 mg a day as an add-on to usual treatment have produced mixed results: an 88-person trial found a small improvement in psychotic symptoms, another found 600 mg no better than placebo, and a small earlier study compared CBD with an established antipsychotic. Taken together, the evidence is interesting but insufficient to treat CBD as an antipsychotic. It is, at least, the opposite of what people fear from a cannabis compound.
CBD and THC together. CBD is often said to soften THC’s psychological effects, but controlled studies have not found reliable protection. In one 2023 trial, 640 mg of oral CBD actually made 20 mg of oral THC more intoxicating and impairing, by slowing its breakdown in the liver.
A wider view helps here. A 2026 review of 54 randomised cannabinoid trials found no significant overall benefit for anxiety or psychotic disorders. That does not erase the individual positive CBD trials, but it puts their size and inconsistency in perspective.
Does it change your brain over time?
Some older articles, including ones on this site that this piece replaces, claimed CBD changes your brain chemistry with regular use. There is no good evidence of that in people, in either direction. Imaging studies show that a single large dose changes activity in some brain regions for a few hours, which is what any active drug does. What weeks or years of use do to the brain has not been studied properly, and the honest answer is that nobody knows. The lack of evidence of harm is reassuring as far as it goes; it is not evidence of benefit.
Dependence and withdrawal
CBD does not appear to be habit-forming. The World Health Organization reviewed it in 2018 and found no evidence of abuse or dependence potential, and a study that stopped people abruptly after four weeks of high-dose treatment found no withdrawal symptoms — four weeks being the only period tested. People who take it every day and stop tend to report that whatever it was doing stops too, which is different from craving it.
Two things worth knowing
The Sydney driving study found something it was not looking for: after a single 1,500 mg dose, CBD was still detectable in some participants’ blood more than four weeks later. CBD is not what drug tests look for, so that is not a testing problem in itself, but it is a reminder that “it wears off in a few hours” is true of the feeling and not of the compound. And because CBD affects how the liver handles other drugs, some of its effects on your mind may also be indirect: raising the levels of a medicine you already take. Our drug interactions guide covers which ones.
The short version
CBD does not produce a THC-like high, and in small studies it did not impair driving or thinking even after very large single doses. At a retail serving, you will most likely feel nothing measurable, though some people report drowsiness. At several hundred milligrams it may take the edge off acute anxiety, can make you sleepy, and in early, mixed trials may slightly ease psychotic symptoms. Whether any of that reaches you from a bottle depends on the dose, and the gap between a gummy and a trial is a reason for caution, not a reason to take more.
Nothing in this article is medical advice. If you have a psychiatric condition or take medication for one, talk to your prescriber before using CBD.
