An overview of current knowledge about the healing effects of cannabis and products from it and its perspectives. Part 1
Abstract
Aim: To briefly review recent knowledge on the lege artis evidence-based medicine use of medical cannabis and products made of it. Tools: A selective review of clinical studies and relevant literature reviews and meta-analyses focusing primarily on the medical use of cannabis and fytocannabinoids.
Results: A substantial part of the clinical research of the treatment effects of cannabis still suffers with several methodological and technical issues. Despite the relatively long history of medical research on cannabis and on substances isolated from cannabis plant, there has been published only relatively small number of sound clinical studies.
The gaps in clinical knowledge are caused by administrative scheduling of cannabis and its major compounds into United Nations Schedule/s of the most dangerous and least medically useful regulated drugs; this obsolete scheduling of cannabis and cannabinoids remains effective even 55 years after the 1961 Single Convention on Drugs went into charge. The research of the medical effects of the whole plant/s is further complicated given that they contain at least 1252 different chemical compounds.
Many of them interact with each other and only within this interaction, they affect the human organism. Such a situation is difficult to fully analyse even with all the steadily growing computing power available for recent research.
Despite all the limitations it is safe to summarise that medical cannabis and products made of it are safe drug of choice for very common symptoms of highly prevalent diseases: (i) mid-severe and severe chronic pain, (ii) spasticity related to neurodegenerative and posttraumatic disorders, and for (iii) treatment of nausea and vomitus be it symptom of the disease itself or of its aggressive (chemo- and/or radiotherapeutic) treatment. Evidence of somewhat lower quality exists for the effectiveness of medical cannabis for treatment of (iv) Parkinson disease, (v) inflammations in general including the idiopathic bowel diseases and Crohn's disease, of the (vi) post-traumatic stress disorder (PTSD), and the (vii) Tourette syndrome.
Despite the wide publicity, only very limited scientific evidence exists on the effectiveness of cannabis and cannabinoids (CBD in particular) for treatment of extremely frequent seizures occurring at refractory epilepsies at very young children (e.g., at Dravet syndrome). There are high hopes that the known cannabis anti-tumour activity, its direct effects on immunity and other homeostasis mechanism will be successfully used for causal (curative) treatment of wide array of diseases in foreseeable future.
However, there is not enough clinical evidence available that would allow introduction of cannabis-based medications for causal treatment recently; the cases of reportedly successful treatment are ostly published by patients and their patients and are not verfiable. Conclusion: When assessed in accord with principles of the Evidence-Based-Medicine, cannabis and products made of it are safe and effective treatment agents for highly prevalent symptoms: pain, spasticity, vomitus and nausea.
While further research of isolated endo-, fyto- and synthetic cannabinoids can widely use the standard research methods, successful studies the effects of the whole plant (and its "entourage effect") would most probably require novel methodologies reflecting somehow different scientific paradigm.