There is no evidence that CBD products reduce chronic pain, and taking them is a waste of money and potentially harmful to health, new research finds

It's important to keep in mind that CBD is, pharmacologically speaking, a very blunt instrument. It's got many demonstrable effects, even if direct alleviation of chronic pain isn't among them. CBD has been studied as a modulator of undesirable effects from THC, which is an effective pain reliever. There's also middling-good evidence from animal and clinical studies that CBD can reduce anxiety and depression.

From this review paper, which is one of the better recent discussions of CBD's psychopharmacology:

CBD has the peculiarity of acting on more than 65 key targets, including the serotonin 1A receptor (5-HT1A), the cannabinoid-related receptors G protein-coupled receptor 55 (GPR55), transient receptor potential vanilloid 1 (TRPV1), type 1 equilibrative nucleoside transporter (ETN1), fatty acid-binding protein (FABP), nuclear factor erythroid 2-related factor 2 (NRF2), voltage-activated T-type calcium channels, adenosine and glycine receptors, mu and delta opioid receptors, and voltage-dependent anion channel 1 (VDAC1), among others [64].

It's also difficult to study a potential drug that has non-linear pharmacokinetics. CBD's effects seem to peak at intermediate doses:

The potential anxiolytic and antidepressant properties of CBD have been examined in several animal models since the late 1970s. Although preliminary findings were contradictory [95,96], subsequent dose-response studies showed that CBD induced an anxiolytic-like effect, which followed an inverted U-shaped curve, resulting effective at intermediate doses but not at low or high doses [97,98,99].

All this being said, cannabidiol isn't a good drug. It's got many different effects and it's too hard to dose reliably (especially with street quality). CBD interacts with multiple other drug families, and the risks are unpredictable in the broader human population without medical supervision.

[Disclosure: I have used commercial full-spectrum hemp tinctures titrated for standardized CBD concentration, theoretically pure CBD, and THC:CBD products. I've noticed mild anxiety reduction from doses ~20 mg CBD, but the pure CBD is harder to work with. For me, 5:1 CBD/THC seems to be a sweet spot for THC pain relief and sleep without excessive psychoactive effects.

Honestly, I don't mess with cannabinoids much anymore because I got an actually effective treatment for the underlying autoimmune disease, but it has drug interactions with almost everything. YMMV.]

Meanwhile the evidence for efficacy of cannabis products containing THC seems strong, and usually show better efficacy with greater ratio of THC to CBD. I think the principle that the medical establishment is working under is that psychoactive = bad, but I suspect it turns out that for many indications the beneficial effects of cannabis are not entirely separable from its psychoactive effects. I think this is also true of opioids.

I thought it was general knowledge by now that for pain you need either THC or CBD+THC and pure CBD advocates usually talk about other benefits than pain? Either way, nice to have some data about it I guess.

This seems to be the section pertaining to linking CBD to adverse health effects. I only quoted the first paragraph of this section, because the following two or three paragraphs are solely about the risk and increase of car accidents, and their increase following marijuana legalization.

Is Pharmaceutical Grade CBD Safe?
This is at best uncertain, but a 2019 systematic review of
CBD adverse events and toxicity in animals and humans
concluded that it was not risk-free.52 Uncertainty also
arises because of the relatively small numbers of patients
in these trials and partly because of inadequacies in re-
porting adverse events.53,54 A meta-analysis of CBD used
for epilepsy found that 10% of patients treated with CBD
had at least 1 adverse event, twice the rate for placebo
and that the risk ratio for serious adverse events was 3.4.55
There appears to be CBD-related hepatotoxicity, with
elevated liver enzymes in about 7% of patients using CBD,
much higher than the rate with placebo.56 Veterans using
cannabinoids for chronic pain have an increased risk of
cannabis use disorder.57

Here is a link to the article they are citing with their statement on liver toxicity. I have so far only skimmed the article's abstract, but it appears to only note effects at doses <300mg daily and also references antiepileptic drug use in conjunction with CBD as a compounding factor. To go from this to stating that any CBD use is a risk to your liver is a stretch, and I'd argue could be at worst fear-mongering.

For a little understanding of my personal biases: I take CBD currently for its affects on my mood, and its help with my anxiety. I do intend to get off it, but I am learning to live with an autoimmune disease and coping with anxiety disorder at the moment, while I wait for testing for ADHD, so I'm gripping on to anything that can help me while I wait extended periods of time for additional help from our medical establishment. This has so far been a 5 years process for me, 3 of which were me being in a great deal of daily pain and discomfort while being told I did not have anything wrong with me, before I was able to diagnose myself with an autoimmune disease by ordering followup blood tests for myself. I am admittedly a little jaded that the medical system has my best interest in mind at least diagnostically.