of cannabis or THC-preparations over the long-term [108]. Although CBD is present in some of these preparations and may inhibit some side effects of THC, there is no certainty that CBD can abolish them all. Furthermore, during the last two decades, the potency of cannabis products has escalated together with a tendency to increase THC and decrease CBD concentrations [11,133,221]. This fact will certainly amplify the negative impact of cannabis self-medication, especially among the young population and patients already severely impacted by depression, anxiety and stress. Some authors of systematic reviews and meta-analyses have concluded that there are no clear benefits in using cannabis and certain cannabinoid preparations in combatting depression and anxiety in the long-term [108,109,128]. This has been accompanied by warnings that long-term cannabis or preparations high in THC may in fact worsen these disorders [108,128]. There is a definite need for more RCT studies, especially in severe mood disorders such as MDD and BD, where there is a lack of such studies. There is expectation of some progress with future studies that consider these pitfalls. Some of these studies are ongoing or at the stage of recruiting subjects [108]. In the interim, it is very difficult to
