The dosages of CBD used in this study are far, far, too low to have any effect. Just like most CBD dosing in commercial situations. Usually scientific investigation use the actual useful dosages of 300-600 mg in humans. I guess these guys didn't do the required background review beforehand.

CBD is not active at the CB1 or CB2 receptors. It has very low affinity for them. It has moderate affinity for the serotonin-1a autoreceptor (that the anti-anxiety medication buspirone also targets). But only at very high dosages (ie, 300mg+).

So... this study has only really tested the placebo effect.

edit: I finished reading the journal article and it turns out they didn't use clinically relevant doses because it'd cost too much. So they decided to just go the placebo route.

>The doses used in this study (25 mg/d to 175 mg/d) were much lower than those reported in some of the clinical literature (300 mg/d to 600 mg/d)12–14,17 for 2 reasons. The first is that in our experience lower doses appear to elicit an adequate clinical response. Second, the current retail cost of CBD would make the use of 600 mg/d cost prohibitive.