Cannabis is known to cause a range of clinical symptoms, including motor coordination problems, euphoria, anxiety, a sense of decreased time, dry mouth, conjunctival injection and tachycardia. While delirium due to cannabis poisoning is described in the DSM-IV-TR, it is a rare clinical condition. Recent studies have explored the potential of CBD to reduce drug-induced psychotic symptoms and cognitive impairment following exposure to high levels of THC. Cannabidiol (CBD) is a phytocannabinoid found in cannabis plants and is thought to lack pharmacological effects.
However, subsequent studies in animals and human volunteers have shown that it can reduce drug-induced psychotic symptoms and cognitive impairment following exposure to high levels of THC, potentially through the endocannabinoid system. CBD is a CB1 receptor antagonist, meaning it will never cause the “high” commonly associated with cannabis use and may counteract CB1 activation after exposure to THC. To understand the potential benefit of CBD as a stand-alone treatment for psychosis, more research is needed. However, studies that indicated the potential benefits of CBD in psychosis tended to be observational case and cohort studies, limiting firm conclusions about the efficacy of CBD.
When CBD was given as a complementary treatment in most studies, patients showed a reduction in psychotic symptoms and an improvement in functional and cognitive abilities compared to those who received placebo. The researchers concluded that CBD could partially normalize alterations in areas of the brain involved in the development of psychosis. In addition, patients treated with CBD showed modest improvements in cognition and the impact of their illness on their quality of life and overall functioning. Overall, while more research is needed to understand the full potential of CBD as a stand-alone treatment for psychosis, current evidence suggests that it may be beneficial for reducing delirium symptoms.