Cannabis use and violence in patients with severe mental illnesses: A meta-analytical investigation

Dellazizzo, Laura; Potvin, Stéphane; Beaudoin, Mélissa; Luigi, Mimosa; Dou, Bo Yi; Giguère, Charles–Édouard; Dumais, Alexandre

doi:10.1016/j.psychres.2019.02.010

Cited by 40 publications

(34 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, heavy and regular cannabis consumption could increase the likelihood of anxiety, depression, suicidal ideation and tendencies, manic episodes, and psychosis [5][6][7] . Among individuals with mental illnesses, cannabis use is associated with more severe symptomatology 5,8 and with violent behaviors 9,10 .…”

Section: Introductionmentioning

confidence: 99%

“…Results from a recent meta-analysis suggest that cannabis use significantly aggravates violent behaviors among people with severe mental illness, with an odds ratio (OR) of 3.02 (95% confidence interval [CI] = 2.01-4.54, p = 0.0001) 10 . This association's strength increases when the use of cannabis persists through time, as demonstrated in a study previously carried out by our research team, which involved patients with various mental disorders 9 .…”

Section: Introductionmentioning

confidence: 99%

“…This association's strength increases when the use of cannabis persists through time, as demonstrated in a study previously carried out by our research team, which involved patients with various mental disorders 9 . However, only two studies included in the metaanalysis 10 focused exclusively on schizophrenia 25,26 : their designs were cross-sectional and their sample sizes were very small (N = 70 and 59). Two other studies calculated a cannabis-violence association in early psychosis patients, but neither created longitudinal models to confirm the directionality of this association 27,28 .…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Persistent cannabis use as an independent risk factor for violent behaviors in patients with schizophrenia

et al. 2020

Self Cite

View full text Add to dashboard Cite

Although recent studies have shown a moderately strong association between cannabis use and violence among people with severe mental disorders, the direction of this association has not been investigated prospectively in a population with schizophrenia. Therefore, this study aims to determine, using cross-lag models, whether a temporal relationship between cumulative cannabis use and violence exists in a population with schizophrenia. The authors reported findings covering an 18month period from a randomized, double-blind clinical trial of antipsychotic medications for schizophrenia treatment. Among the 1460 patients enrolled in the trial, 965 were followed longitudinally. Although persistent cannabis use predicted subsequent violence, violence did not predict cannabis use. The relationship was therefore unidirectional and persisted when controlling for stimulants and alcohol use. Finally, a significant body of evidence suggests a link between persistent cannabis use and violence among people with mental illnesses. Studies to further investigate the mechanisms underlying this association should be conducted.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Persistent cannabis use as an independent risk factor for violent behaviors in patients with schizophrenia

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…In addition, the rate of CU is often high in subgroups of violent patients (VPs) with psychotic disorders [13,[22][23][24][25][26]. However, research exploring the links between CU considered specifically and VB in psychosis is still rare [23,24,[27][28][29][30][31][32] and their results are controversial due to methodological limitations and because studies have not always controlled for important confounding risk factors [31,[33][34][35].…”

Section: Introductionmentioning

confidence: 99%

Early onset of cannabis use and violent behavior in psychosis

et al. 2020

View full text Add to dashboard Cite

Background: Although evidence from psychosis patients demonstrates the adverse effects of cannabis use (CU) at a young age and that the rate of CU is high in subgroups of young violent patients with psychotic disorders, little is known about the possible effect of the age of onset of CU on later violent behaviors (VB). So, we aimed to explore the impact of age at onset of CU on the risk of displaying VB in a cohort of early psychosis patients. Method: Data were collected prospectively over a 36-month period in the context of an early psychosis cohort study. A total of 265 patients, aged 18–35 years, were included in the study. Logistic regression was performed to assess the link between age of onset of substance use and VB. Results: Among the 265 patients, 72 had displayed VB and 193 had not. While violent patients began using cannabis on average at age 15.29 (0.45), nonviolent patients had started on average at age 16.97 (0.35) (p = 0.004). Early-onset CU (up to age 15) was a risk factor for VB (odds ratio = 4.47, confidence interval [CI]: 1.13–20.06) when the model was adjusted for age group, other types of substance use, being a user or a nonuser and various violence risk factors and covariates. History of violence and early CU (until 15) were the two main risk factors for VB. Conclusions: Our results suggest that early-onset CU may play a role in the emergence of VB in early psychosis.

show abstract

“…We conducted a meta-analysis to examine the association between cannabis use/misuse and the perpetration of violence in adult individuals with SMD (schizophrenia, schizophreniform disorder, schizoaffective disorder, delusional disorder, bipolar disorder, and major depression) (36). Notably, these individuals are already at an elevated risk of violence in comparison to the general population (37,38).…”

Section: Individuals With Severe Mental Disordersmentioning

confidence: 99%

Violence and Cannabis Use: A Focused Review of a Forgotten Aspect in the Era of Liberalizing Cannabis

et al. 2020

Self Cite

View full text Add to dashboard Cite

There has been a shift surrounding societal and legal perspectives on cannabis reflecting changing public attitudes towards the perceived safety and social acceptability of cannabis use. With cannabis liberalization internationally, the focus of most cannabisrelated harms has been on effects with users themselves. Harm-to-others including injuries from violence have nevertheless been unfortunately largely overlooked. While studies remain heterogeneous, there is meta-analytical evidence pointing towards an association. The aims of this focused review are twofold: (I) review the evidence from meta-analyses on the association between cannabis and violence; and (II) provide an overview of possible mechanisms relating cannabis use to violence. First, evidence from meta-analytical studies in youths, intimate partners, and individuals with severe mental disorders have shown that there is a global moderate association between cannabis use and violence, which is stronger in the latter more at-risk population. Preliminary data has even highlighted a potential dose-response relationship with larger effects in more frequent users. Although of importance, this subject has remained essentially forgotten as a public health concern. While literature remains inconclusive, data has suggested potential increases in cannabis use following liberalization policies. This may increase violent outcomes if the effect is directly related to the use of cannabis by means of its psychophysiological modifications. However, for the moment, the mechanisms associating cannabis use and violence remain to be clearly resolved. Considering the recency of policy changes on cannabis, further methodologically sound research using longitudinal designs should examine the effects that cannabis use may have on different forms of violence and the trends that emerge, while evaluating the effects of possible confounding factors (e.g. other substance use). In addition, as evidence-based research from meta-analyses have shown that cannabis use is associated with violence, measures must be taken to mitigate the risks.

show abstract

Cannabis use and violence in patients with severe mental illnesses: A meta-analytical investigation

Cited by 40 publications

References 33 publications

Persistent cannabis use as an independent risk factor for violent behaviors in patients with schizophrenia

Persistent cannabis use as an independent risk factor for violent behaviors in patients with schizophrenia

Early onset of cannabis use and violent behavior in psychosis

Violence and Cannabis Use: A Focused Review of a Forgotten Aspect in the Era of Liberalizing Cannabis

Contact Info

Product

Resources

About