“Let’s say THC is the ‘bad guy’ in cannabis. However, fortunately there is also a ‘good guy’ in cannabis, called cannabidiol,” Bossong said. “There is quite some evidence that it has antipsychotic properties.” Along with German and Italian researchers, scientists at the University of California, Irvine conducted a double-blind, randomized, clinical trial comparing the effects of cannabidiol with those of the antipsychotic medication amisulpride.6

Their findings, which were reported in 2012 in Translational Psychiatry, show that both treatments led to significant clinical improvement, but cannabidiol resulted in fewer of the common side effects —  including motor impairments and weight gain — that substantially influence non-compliance with antipsychotic medications.

“These findings have to be confirmed in larger clinical trials, but they are very promising,” said Bossong. “Future studies that could be done are neuropsychological and neuroimaging studies that look at brain function of schizophrenia patients before and after cannabidiol treatment, to examine if it is able to normalize their impaired brain function.”

Tori Rodriguez, MA, LPC, is a psychotherapist and freelancer writer based in Atlanta.


  1. Cassidy CM, et al. Do reward processing deficits in schizophrenia-spectrum disorders promote cannabis use? An investigation of physiological response to natural rewards and drug cues. Journal of Psychiatry and Neuroscience. 2014; 39(5):339-47.
  2. Fischer AS, et al. Impaired functional connectivity of brain reward circuitry in patients with schizophrenia and cannabis use disorder: Effects of cannabis and THC. Schizophrenia Research. 2014; 158(1-3):176-82.
  3. Bossong MG, et al. Role of the endocannabinoid system in brain functions relevant for schizophrenia: An overview of human challenge studies with cannabis or Δ9-tetrahydrocannabinol (THC). Progress in Neuro-Psychopharmacology & Biological Psychiatry. 2014; 52; 53–69.
  4. Compton WM, et al. Prevalence of marijuana use disorders in the United States: 1991-1992 and 2001-2002. JAMA. 2004; 291(17):2114-21.
  5. Power RA, et al. Genetic predisposition to schizophrenia associated with increased use of cannabis. Molecular Psychiatry. 2014; 19(11):1201-4.
  6. Leweke FM, et al. Cannabidiol enhances anandamide signaling and alleviates psychotic symptoms of schizophrenia. Translational Psychiatry. 2012; 2, e94.