TenForward: Where Every Vulcan Knows Your Name

The paper and supplemental materials you provided didn't explain their decision making on how they are representing their opinion on them, but here's the abstracts of the four papers they concluded as no effect (and as a reminder, OP was asking about paranoia, not psychosis).

Post-THC, there were lower PANSS positive scores in the CBD group, but this did not reach statistical significance. However, clinically significant positive psychotic symptoms (defined a priori as increases ≥ 3 points) were less likely in the CBD group compared with the placebo group, odds ratio (OR)=0.22 (χ²=4.74, p<0.05). In agreement, post-THC paranoia, as rated with the State Social Paranoia Scale (SSPS), was less in the CBD group compared with the placebo group (t=2.28, p<0.05).

• Englund et al. Cannabidiol inhibits THC-elicited paranoid symptoms and hippocampal-dependent memory impairment (2013)

In a second experiment, six healthy volunteers were administered Delta-9-THC intravenously on two occasions, after placebo or CBD pretreatment to examine whether CBD could block the psychotic symptoms induced by Delta-9-THC. […] In the second experiment, pretreatment with CBD prevented the acute induction of psychotic symptoms by Delta-9-tetrahydrocannabinol.

• Bhattacharyya et al. Opposite effects of delta-9-tetrahydrocannabinol and cannabidiol on human brain function and psychopathology (2010)

Results indicated that THC increased overall scores on the PSI, negative symptoms on BPRS, and robustly impaired episodic and working memory. Co-administration of CBD did not attenuate these effects. CBD alone reduced PSI scores in light users only. At a ratio of 2:1, CBD does not attenuate the acute psychotic and memory impairing effects of vaporised THC.

• Morgan et al. Individual and combined effects of acute delta-9-tetrahydrocannabinol and cannabidiol on psychotomimetic symptoms and memory funct (2018)

The fourth study was in conference notes and this appears to be only one of two studies to cite it. The same cited author the same year contributed to the review Cannabidiol as a Potential New Type of an Antipsychotic. A Critical Review of the Evidence (2016) which focused on a study the Lancet piece you cited appears not to have included:

The first controlled, randomized, double-blind clinical trial was conducted by Leweke et al. (2012). During this 4-week trial 42 schizophrenic patients received either cannabidiol (600–800 mg/day) or amisulpride (600–800 mg/day) – a highly effective second generation antipsychotic, selectively antagonizing D2/3 receptors (Leucht et al., 2002). Both drugs resulted in significant clinical improvement of both positive and negative symptoms of psychosis. The efficacy of cannabidiol was comparable to that of amisulpride, but, importantly, cannabidiol revealed a superior side effect profile when compared to amisulpride.

That paper has over 900 citations.

The Lancet is a gold standard, presumably they had their reasons to count the conference notes results twice in both CBD only and CBD+THC's handful of studies that made their cut but not include this one.

Now…

If this was a user in the midst of a psychotic break thinking of just adding in CBD but keeping up with THC, or someone with schizophrenia, my advice would be to avoid the THC because of the potential harms.

But OP was asking about paranoia.

And so yes there's studies where CBD has been shown to be an effective antipsychotic on its own.

And there is evidence to support that CBD reduces the effects of THC via fMRI and paranoia evaluation.

There is also conflicting evidence as to the reduction of the psychosis effects of THC when high. Which OP isn't expressing concern about.

(Additionally, even if it were only as effective as placebo for paranoia, placebo effects are notably large for generalized anxiety, at 1.85 in Huneke et al, Placebo effects in randomized trials of pharmacological and neurostimulation interventions for mental disorders: An umbrella review (2024).)

Also, looking over things again now (and thanks for pushing it), the evidence seems like CBD may be less likely to be having measurable effect when vaporized vs other delivery routes. So ymmv.

TL;DR: The side effect profile for CBD is minimal, and for a user simply concerned with not feeling paranoid when high, it's perfectly safe and appropriate to suggest adding it into the mix to see if it reduces the paranoia, as well as pointing out the plausible existing evidence for there being an effect.