CBD and Depression: What Studies Show and Safety Limits

If you need help now

If you are thinking about suicide or feel you cannot keep yourself safe, call your local emergency number. In the EU that is 112 (opens in a new tab), and in the UK it is 999. For someone to talk to, the free European emotional support number 116 123 (opens in a new tab) works in most, though not all, EU countries. In the UK, 116 123 reaches Samaritans, and NHS 111 has a mental health option (NHS (opens in a new tab)).

Low mood and depression are not the same thing

The World Health Organization describes a depressive episode as a depressed mood or loss of interest that lasts most of the day, nearly every day, for at least two weeks, and says it differs from ordinary mood changes (WHO, 2026 (opens in a new tab)). The same fact sheet states that effective treatment exists for mild, moderate and severe depression.

That distinction matters when you read about CBD. A study of stressed students, a study of people with a brain tumour and a study of people with bipolar disorder are measuring different things, even when all three report a "depression score".

What CBD and depression studies have found

Animal studies

Most of the research so far is in rodents. A 2020 review describes CBD producing antidepressant-like effects in mice and rats, both alone and alongside low doses of the antidepressants fluoxetine and desipramine, with several studies pointing to serotonin 5-HT1A receptors (García-Gutiérrez et al., 2020 (opens in a new tab)). The effects depended on the dose, the animal strain, how long CBD was given and how it was given. The same review describes the human evidence as "still scarce", so results in rodents still need to be confirmed in people.

Trials in people

The 2019 Lancet Psychiatry review included 42 studies on depression, 23 of them randomised trials with 2,551 participants (Black et al., 2019 (opens in a new tab)). In most of the depression and anxiety trials, people took a cannabinoid for another condition, mainly chronic pain or multiple sclerosis, and few trials examined pharmaceutical CBD (full text (opens in a new tab)). The authors wrote that "further high-quality studies directly examining the effect of cannabinoids on treating mental disorders are needed."

Placebo-controlled trials published since then:

In the bipolar trial, an exploratory analysis looked at the 22 people whose dose was raised to 300 mg/day. In that subgroup, depression scores fell more on CBD than on placebo between weeks 2 and 8 (Pinto et al., 2023 (opens in a new tab)). The authors want this tested in larger trials designed to account for the high placebo response they saw.

A 2025 scoping review of randomised trials of medicinal cannabis for mental health conditions, published from 1980 to 2024, found 28 trials, one of them in depression: the bipolar trial above, which found no significant difference from placebo (Cooling et al., 2025 (opens in a new tab)).

The next step is bigger. A registered phase 3 trial of CBD in bipolar depression plans to enrol 360 people and expects to finish in 2030 (ClinicalTrials.gov, NCT05867849 (opens in a new tab)).

Surveys of CBD users

In an online survey of 2,409 CBD users, people reported mood-improving effects across several medical conditions (García-Gutiérrez et al., 2020 (opens in a new tab)). The review notes that the survey did not separate pure CBD from cannabis-derived products containing other compounds. A survey also has no placebo group, and the 2025 student trial above shows how large the placebo response to an oil can be.

A 2022 Polish study of 90 people using CBD to self-treat depression found that 19 % had asked a doctor or pharmacist about it. Among those who were psychiatric patients, 49 % had told their psychiatrist (Wieckiewicz et al., 2022 (opens in a new tab)).

CBD and antidepressants

CBD interacts with cytochrome P450, the family of liver enzymes that breaks down many prescription medicines. A 2021 review of CBD interactions reported that CBD inhibits the enzyme CYP2D6, which can raise blood levels of SSRIs and tricyclic antidepressants (Balachandran et al., 2021 (opens in a new tab)). The same review lists possible interactions with MAO inhibitors and notes that citalopram, paroxetine and mirtazapine are broken down by enzymes CBD is known to inhibit. It adds that many reported interactions still need human trials to judge how much they matter in practice.

The product information for Epidyolex, the prescription CBD medicine, states that CBD inhibits CYP2C19 and that dose reduction should be considered for sensitive medicines processed by that enzyme (Epidyolex SmPC (opens in a new tab)). It also states that alcohol and other medicines that slow the nervous system can add to CBD's sleepiness and sedation.

None of the sources reviewed for this article reports human data on CBD and serotonin syndrome. That is a gap in the evidence, so ask your pharmacist rather than assume either way.

Regulators take a cautious line here. EFSA concluded that the safety of CBD as a food "cannot be established" for people on medication (EFSA, 2026 (opens in a new tab)). The UK Food Standards Agency does not recommend CBD for people taking any medication unless under medical direction (FSA (opens in a new tab)). Our guide to CBD interactions with prescription medicines covers other drug groups.

Can CBD cause depression or low mood?

None of the trials above was designed to answer that question. The safety data in the sources reviewed here report the following:

• In epilepsy trials of Epidyolex, at 10 to 25 mg per kg of body weight per day, irritability and aggression were reported as common side effects, and sleepiness, fatigue and decreased appetite as very common (Epidyolex SmPC (opens in a new tab)).
• The same document carries the warning given for all anti-epileptic medicines: suicidal thoughts and behaviour have been reported with this drug class, and the available data "do not exclude the possibility of an increased risk for cannabidiol".
• In the 2026 brain tumour trial, clinically significant anxiety was present in 59 % of participants after CBD and 50 % after placebo (Belgers et al., 2026 (opens in a new tab)).
• In the 2023 bipolar trial, the CBD and placebo groups did not differ in manic symptoms or other adverse effects (Pinto et al., 2023 (opens in a new tab)).

If your mood changes after starting CBD or any new product, tell your doctor. The reported CBD side effects article covers liver effects and who regulators say should avoid CBD.

How much CBD did the studies use?

The bipolar and brain tumour trials gave 150 to 600 mg of CBD a day under medical supervision, and the student trial used a low-dose over-the-counter oil (Pinto et al., 2023 (opens in a new tab); Winkler et al., 2025 (opens in a new tab); Belgers et al., 2026 (opens in a new tab)). These are study protocols, not a recommendation. If you are thinking about CBD while being treated for depression, agree it with your doctor.

Where the research stands

The 2019 Lancet Psychiatry review found few randomised trials of pharmaceutical CBD for mental health conditions (Black et al., 2019 (opens in a new tab)), and the 2025 scoping review found one depression trial among 28 (Cooling et al., 2025 (opens in a new tab)). Most human data so far come from small trials, and the 360-person phase 3 trial is the next large test.

Epidyolex, the CBD medicine authorised across the EU, is approved for seizures linked to specific epilepsy syndromes (EMA (opens in a new tab)). It is not authorised for depression.

Is CBD safe for young adults?

EFSA concluded in February 2026 that the safety of CBD as a novel food cannot be established for people under 25 (EFSA, 2026 (opens in a new tab)), and our guide to who regulators say should avoid CBD lists the other groups.

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