Wednesday, 10 July 2013

Cannabidiol, the novel natural and well-tolerated antipsychotic

It's intriguing that while we were searching for means to ameliorate the suffering of schizophrenic individuals with pharmaceutics, nature had already provided us with a means of alleviating their suffering from a most unlikely source: the cannabis sativa plant. The cannabis sativa plant, also known as the marijuana plant, contains a compound that has, of late, been found to possess prominent antipsychotic effects comparable to the antipsychotic drug amisulpride (if you want to put the efficacy of amisulpride into perspective since, of course, different drugs have different efficacy in treating the wide range of conditions out there, amisulpride has been found to be the 2nd most effective antipsychotic, behind the infamous antipsychotic clozapine, according to two meta analyses of clinical trial data) in patients with schizophrenia. This compound is known as cannabidiol, and unlike many of the other "active" constituents of cannabis its effects are in opposition with the psychoactive effects of infamous, chief psychoactive constituent of the cannabis plant, tetrahydrocannabinol (THC).1

Unlike amisulpride, however, which is notorious for its ability to prolong the QT interval (in other words alter the electrical activity of the heart in a way that can lead to potentially fatal irregularities in heart rate), elevate blood prolactin levels (which can lead to the enlargement of breast tissue in men, and even galactorrhoea [the release of milk] even in males, and can, after long-term elevation lead to osteoporosis [brittle bones] and sexual dysfunction in both sexes), cause Parkinson's disease-like side effects (i.e. tremor, trouble initiating and stopping movement, etc.), obesity and even cause type II diabetes mellitus and cardiovascular disease, cannabidiol in this trial seldom even caused any side effects and when it did they were mild. 

Cannabidiol also appears to have an added advantage over many antipsychotics in that it appears to have prominent antidepressant,2 anxiolytic (anti-anxiety)3 and antineoplastic (anti-cancer) effects4 which may be advantageous in schizophrenic patients seeing how they have a heightened risk of suicide, anxiety and premature death due to, among other things, cancer (interestingly approximately 80% of them smoke tobacco compared to around 20% of the general population). Cannabidiol is also known to possess some anticonvulsant (seizure preventing and suppressing) effects5 and hence may be advantageous when used to augment (improve responses to) existing regimens of antipsychotics which can, albeit rarely, cause seizures.


  1. Leweke FM, Piomelli D, Pahlisch F, Muhl D, Gerth CW, Hoyer C, et al. Cannabidiol enhances anandamide signaling and alleviates psychotic symptoms of schizophrenia. Transl Psychiatry [Internet]. 2012 Mar 20 [cited 2013 Jul 10];2(3):e94. Available from:
  2. Zanelati T, Biojone C, Moreira F, Guimaraes F, Joca S. Antidepressant-like effects of cannabidiol in mice: possible involvement of 5-HT1A receptors. Br J Pharmacol [Internet]. 2010 Jan [cited 2013 Jul 10];159(1):122–8. Available from:
  3. Schier AR de M, Ribeiro NP de O, Silva AC de O e, Hallak JEC, Crippa JAS, Nardi AE, et al. Cannabidiol, a Cannabis sativa constituent, as an anxiolytic drug. Revista Brasileira de Psiquiatria [Internet]. 2012 Jun [cited 2013 Jul 10];34:104–10. Available from:
  4. Massi P, Solinas M, Cinquina V, Parolaro D. Cannabidiol as potential anticancer drug. British Journal of Clinical Pharmacology [Internet]. 2013 [cited 2013 Jul 10];75(2):303–12. Available from:
  5. Cunha JM, Carlini EA, Pereira AE, Ramos OL, Pimentel C, Gagliardi R, et al. Chronic Administration of Cannabidiol to Healthy Volunteers and Epileptic Patients. Pharmacology [Internet]. 1980 [cited 2013 Jul 10];21(3):175–85. Available from:

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