Digipath Blog

By Cindy Orser, PhD, Chief Science Officer of Digipath Labs

‘Cannabis Use Disorder,’ or CUD for short is described as a new mental health condition categorized in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), the diagnostic bible of psychiatrists.  The DSM publication is used by clinicians, researchers, drug regulatory agencies, health insurance companies, pharmaceutical companies, lawyers and courts and policy makers.  Once a human condition has become medicalized then it becomes fair game for the justification of psychiatric doctor visits and pharmaceutical treatment for yet one more nuanced mental disorder.

With the printing of DSM-5, the number of syndromes, including ‘Cannabis Use Disorder,’  continued to climb from 106 in DSM-1 to now more than 360 in DSM-5!   Psychiatrists have a statistical CUD patient defined as an adult seeking treatment who has consumed cannabis daily for greater than 10 years and tried to quit unsuccessfully several times on their own.  What does it mean to be diagnosed with a mental illness or disorder?  It means that a doctor or group of doctors have decided that you suffer from a condition which causes a behavioral or mental pattern that may cause “suffering or a poor ability to function in life,” with signs and symptoms varying widely.

Phytocannabinoids are compatible with our endocannabinoid receptors and exert broad physiological responses, contracting some muscles while relaxing others, relieving pain and inflammation, directing apoptosis and orchestrating connections between the gut and the brain.  There is growing concern for the unknown chronic effects on both mental and physical health through self-administration of highly purified THC combined with more direct and immediate modes of delivery.  There are peer-reviewed publications with neuroimages of heavy cannabis smokers’ brains concluding that in those regions of the brain with high CB-1 receptor expression, ie. the hippocampus and prefrontal cortex, there are deformities.[1]  The causal link between those neuroanatomical changes and the potency of ever higher THC content marijuana containing lower levels of the neuroprotective cannabidiol (CBD) may be a contributing factor but the existing human cannabis exposure data is fragmented, limited and does not lead to an evidence-based guideline for how to accurately quantify cannabis exposure in human studies let alone draw behavioral or mental health conclusions.

So what we have is an opportunity.  We desperately need neurobiology to come up to speed with public policy and the rolling wave of legalization of both medical marijuana as well as recreational marijuana.  We need controlled animal and human studies to yield objective data about cannabis use and neurological or other models of cannabis exposure.  We need to understand the impact of specific cannabinoids alone and in combination, their dosage and duration of dosage as it affects the brain.   Once we have unbiased cannabis user and exposure data, we should analysis the data before giving the diagnosis.  Only objective, unbiased human data can be used to develop a working hypothesis of the risks and benefits of cannabis to health disorders.

[1] Lorenzetti V, et al. (2016) The Role of Cannabinoids in Neuroanatomical Alterations in Cannabis Users.  Biological Psychiatry http://dx.doi.org/10.1016/j.biopsych.2015.11.013