No Images? Click here In This Issue - June 2018Guest Article: Dr.Mohammed Warsi and Dr. Alexander Dufort on Cannabis and Psychosis
Despite some uncertainty on the specific date, recreational (non-medical) cannabis consumption will be legal in Canada in 2018. While it is the federal government that is mandating this legalization, it is up to each individual province to decide on the regulations regarding its sale and consumption. In Ontario, cannabis use will be legal for individuals 19 years old and over. Use will be allowed in private residences but otherwise prohibited in public spaces. Users will be able to buy up to 30 grams of cannabis either in person or online through the Ontario Cannabis Store. Individuals with a green thumb will be able to grow up to four cannabis plants of their own.Despite the fast approaching legalization and the many purported medicinal benefits (often with the absence of evidence), there are still many concerns regarding the use of cannabis. Many of these concerns are related to possible negative mental health outcomes, the worst of which being the development and exacerbation of psychosis. This newsletter will provide information regarding the effects of cannabis use on psychosis. Epidemiology of cannabis use: Before discussing the specific risks of cannabis use, it is first important to understand how common the use of this substance has become. The rate of past year cannabis use across Canada, amongst all age groups and both genders was estimated to be 12.6%, more than double the rate documented in 1985. Use among minors was 17.5%. More locally, approximately 1 out of 5 grade 7-12 Ontario students reported trying cannabis at least once in past year, a higher rate than tobacco use. Niagara specific data echoes these statistics (1). Despite these seemingly high numbers, there is evidence that use amongst individuals aged 15-25 is either stable or decreasing. More data on use by adolescents can be gleaned from the United States where legalization has already taken place in several states. While general use has increased in states such as Colorado, use among children aged 12-17 has decreased (National Survey on Drug Use and Health). Proponents of legalization suggest that this decrease was due to strict penalties for selling the drug to minors, similar to regulations which would be in place in Ontario (2). Whether the rates of use increase or not, there is no denying that cannabis use is widespread and that this pervasiveness may magnify any adverse effects. Cannabis and psychosis: Does cannabis use cause psychosis? The casual association between cannabis and psychosis has been the focus of much attention over the years. As with many substances (i.e. cocaine, methamphetamine), cannabis use can lead to an acute substance induced psychosis, an illness that is generally short lived and resolves with sustained abstinence from the causal drug. While acute psychosis can be debilitating and distressing, the primary concern is whether cannabis use leads to the development of chronic psychotic illness such as schizophrenia. To that end, recent research has demonstrated that up to 50% of individuals suffering from cannabis induced psychosis go on to be diagnosed with schizophrenia(3). In addition to following individuals with substance induced psychosis, several longitudinal studies have monitored cannabis users from adolescent into adulthood. A landmark systematic review and meta-analysis in this field analyzed 11 longitudinal studies. The authors of this paper reported that individuals that used cannabis at least once were 40% more likely to develop a psychotic illness, including schizophrenia. This paper also documented a dose-dependent relationship where heavy users could be up to 200% more likely to develop a psychotic illness(4). While this evidence does not prove causality it certainly seems to indicate that cannabis use is a risk factor for the future development of psychosis. What are the effects of cannabis use in individuals with a pre-existing psychotic illness? The effects of cannabis use in individuals with pre-existing psychotic illness are well known and not as debated as the previous question. A recent meta-analysis of 24 studies found that ongoing cannabis use in patients with schizophrenia was associated with poorer functioning, exacerbated positive symptoms, more frequent relapses and lengthier hospital admissions(5). These effects are especially troubling given the high rates of cannabis use within the patient population, with some studies estimating that 24% of patients with schizophrenia also suffer from a comorbid cannabis use disorder(6). It is important to note that not all strains of cannabis are created equal and that different constituents of the drug seem to have opposing effects. The main psychoactive compound of cannabis, delta-9-tetrahydrocannabinol (THC), seems to be linked to the development and exacerbation of psychosis. On the other hand, cannabidiol (CBD) seems to attenuate the effects of THC and may actually have some antipsychotic properties as documented in a recent RCT. Additional research suggests that use of strains containing a higher ratio of CBD:THC may reduce the risk of psychosis and other undesirable cognitive effects(7). Recommendations: Based on the above, it is clear that cannabis use is widespread and it is likely that use may lead to the development of psychosis. Despite this evidence, legalization is a reality and an increase in use is a possibility. To help clinicians approach this problem, we have provided the following recommendations adapted from the Canadian Schizophrenia Guidelines and the Canadian Consortium for Early Intervention in Psychosis (8).
Cannabis (THC) use in youth significantly increases the risk of psychosis while the effects of CBD remain uncertain.
Dr. M. A. Warsi is a psychiatrist with Niagara Region Mental Health and Academic Lead for Psychiatry at McMaster University Regional Campus. Dr. Alexander Dufort is a second year resident in the Department of Psychiatry and Behavioural Neurosciences at McMaster University. For additional information or questions contact 905-688-2854. Symptoms of Psychosis: Common symptoms that may be signs of psychosis:
Individuals (from 14-35 years old) suffering from their first episode of psychosis or with suspected psychotic symptoms should be referred to the Niagara Region Early Psychosis Intervention Service or the emergency department as appropriate. Additional Mental Health Resources: For patients who are not experiencing psychosis or psychotic symptoms but require brief, single-session support for other mental health concerns, the following community walk-in programs are available: Children and Youth: Pathstone Mental Health Immediate mental health counselling for children and youth (ages 6 to 17 years) and their parents/caregivers is available at the Walk-In Clinic at Branscombe Mental Health Centre located at 1338 Fourth Avenue in St. Catharines. Held weekly on Tuesday, Wednesday and Thursday from 9 a.m. until 4:30 p.m. (last appointment at 3:30 p.m.)
Adults: Canadian Mental Health Association CMHA Niagara has immediate services, for individuals (16+ years of age) experiencing emotional distress with Urgent Support Services and for individuals looking to make a change with “A Session at a Time” Walk In Counselling. Individuals may self-refer by visiting a location or calling 905-641-5222. Urgent Support hours are Monday to Friday 11:30 a.m. until 5:30 p.m. at:
“A Session at a Time’ Walk In Counselling hours are 11:30 a.m. until 5:30 p.m.
Niagara Region Public Health Public Health offers a range of services through the Mental Health program in addition to the Early Psychosis Intervention Service. To make a referral to any of the other Mental Health programs, call 905-688-2854 ext. 7262 or use the online referral forms. To order patient resources, please visit the Health Care Provider site. Drug Addiction and Detox Programs in Niagara: For patients that are interested in treatment for cannabis use and addiction, there are support agencies offering counselling, treatment, information and phone line support for alcohol and drug addictions. Click here for more information. References
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