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Zellers S, Alexander J, Ellingson JM, Schaefer JD, Corley RP, Iacono W, Hewitt JK, Hopfer CJ, McGue MK, Vrieze S. Limited psychological and social effects of lifetime cannabis use frequency: Evidence from a 30-year community study of 4,078 twins. JOURNAL OF PSYCHOPATHOLOGY AND CLINICAL SCIENCE 2024; 133:115-128. [PMID: 38147055 PMCID: PMC10751959 DOI: 10.1037/abn0000867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
BACKGROUND Cannabis use is associated with outcomes like income, legal problems, and psychopathology. This finding rests largely on correlational research designs, which rely at best on statistical controls for confounding. Here, we control for unmeasured confounders using a longitudinal study of twins. METHOD In a sample of 4,078 American adult twins first assessed decades ago, we used cotwin control mixed effects models to evaluate the effect of lifetime average frequency of cannabis consumption measured on substance use, psychiatric, and psychosocial outcomes. RESULTS On average, participants had a lifetime cannabis frequency of about one to two times per month, across adolescence and adulthood. As expected, in individual-level analyses, cannabis use was significantly associated with almost all outcomes in the expected directions. However, when comparing each twin to their cotwin, which inherently controls for shared genes and environments, we observed within-pair differences consistent with possible causality in three of the 22 assessed outcomes: cannabis use disorder symptoms (βW-Pooled = .15, SE = .02, p = 1.7 × 10-22), frequency of tobacco use (βW-Pooled = .06, SE = .01, p = 1.2 × 10-5), and illicit drug involvement (βW-Pooled = .06, SE = .02, p = 1.2 × 10-4). Covariate specification curve analyses indicated that within-pair effects on tobacco and illicit drug use, but not cannabis use disorder, attenuated substantially when covarying for lifetime alcohol and tobacco use. CONCLUSIONS The cotwin control results suggest that more frequent cannabis use causes small increases in cannabis use disorder symptoms, approximately 1.3 symptoms when going from a once-a-year use to daily use. For other outcomes, our results are more consistent with familial confounding, at least in this community population of twins. (PsycInfo Database Record (c) 2023 APA, all rights reserved).
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Affiliation(s)
- Stephanie Zellers
- Department of Psychology, University of Minnesota
- Institute for Molecular Medicine Finland, University of Helsinki
| | | | - Jarrod M. Ellingson
- Department of Psychiatry, University of Colorado Anschutz Medical Campus
- Institute for Behavioral Genetics, University of Colorado Boulder
| | | | - Robin P. Corley
- Institute for Behavioral Genetics, University of Colorado Boulder
| | | | - John K. Hewitt
- Institute for Behavioral Genetics, University of Colorado Boulder
- Department of Psychology and Neuroscience, University of Colorado Boulder
| | - Christian J. Hopfer
- Department of Psychiatry, University of Colorado Anschutz Medical Campus
- Institute for Behavioral Genetics, University of Colorado Boulder
| | | | - Scott Vrieze
- Department of Psychology, University of Minnesota
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Kapler S, Adery L, Hoftman GD, Amir CM, Grigoryan V, Cooper ZD, Bearden CE. Assessing evidence supporting cannabis harm reduction practices for adolescents at clinical high-risk for psychosis: a review and clinical implementation tool. Psychol Med 2024; 54:245-255. [PMID: 37882050 DOI: 10.1017/s0033291723002994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
Cannabis use is consistently associated with both increased incidence of frank psychotic disorders and acute exacerbations of psychotic symptoms in healthy individuals and people with psychosis spectrum disorders. Although there is uncertainty around causality, cannabis use may be one of a few modifiable risk factors for conversion to psychotic disorders in individuals with Clinical High Risk for Psychosis (CHR-P) syndromes, characterized by functionally impairing and distressing subthreshold psychotic symptoms. To date, few recommendations beyond abstinence to reduce adverse psychiatric events associated with cannabis use have been made. This narrative review synthesizes existing scientific literature on cannabis' acute psychotomimetic effects and epidemiological associations with psychotic disorders in both CHR-P and healthy individuals to bridge the gap between scientific knowledge and practical mental health intervention. There is compelling evidence for cannabis acutely exacerbating psychotic symptoms in CHR-P, but its impact on conversion to psychotic disorder is unclear. Current evidence supports a harm reduction approach in reducing frequency of acute psychotic-like experiences, though whether such interventions decrease CHR-P individuals' risk of conversion to psychotic disorder remains unknown. Specific recommendations include reducing frequency of use, lowering delta-9-tetrahydrocannabinol content in favor of cannabidiol-only products, avoiding products with inconsistent potency like edibles, enhancing patient-provider communication about cannabis use and psychotic-like experiences, and utilizing a collaborative and individualized therapeutic approach. Despite uncertainty surrounding cannabis' causal association with psychotic disorders, cautious attempts to reduce acute psychosis risk may benefit CHR-P individuals uninterested in abstinence. Further research is needed to clarify practices associated with minimization of cannabis-related psychosis risk.
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Affiliation(s)
- Simon Kapler
- Semel Institute for Neuroscience and Human Behavior, Departments of Psychiatry and Behavioral Sciences, University of California, Los Angeles, CA, USA
| | - Laura Adery
- Semel Institute for Neuroscience and Human Behavior, Departments of Psychiatry and Behavioral Sciences, University of California, Los Angeles, CA, USA
| | - Gil D Hoftman
- Semel Institute for Neuroscience and Human Behavior, Departments of Psychiatry and Behavioral Sciences, University of California, Los Angeles, CA, USA
| | - Carolyn M Amir
- Semel Institute for Neuroscience and Human Behavior, Departments of Psychiatry and Behavioral Sciences, University of California, Los Angeles, CA, USA
- Neuroscience Interdepartmental Program, University of California, Los Angeles, CA, USA
| | - Vardui Grigoryan
- Semel Institute for Neuroscience and Human Behavior, Departments of Psychiatry and Behavioral Sciences, University of California, Los Angeles, CA, USA
| | - Ziva D Cooper
- Semel Institute for Neuroscience and Human Behavior, Departments of Psychiatry and Behavioral Sciences, University of California, Los Angeles, CA, USA
- UCLA Center for Cannabis and Cannabinoids, University of California, Los Angeles, CA, USA
| | - Carrie E Bearden
- Semel Institute for Neuroscience and Human Behavior, Departments of Psychiatry and Behavioral Sciences, University of California, Los Angeles, CA, USA
- Department of Psychology, University of California, Los Angeles, CA, USA
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Guma E, Cupo L, Ma W, Gallino D, Moquin L, Gratton A, Devenyi GA, Chakravarty MM. Investigating the "two-hit hypothesis": Effects of prenatal maternal immune activation and adolescent cannabis use on neurodevelopment in mice. Prog Neuropsychopharmacol Biol Psychiatry 2023; 120:110642. [PMID: 36150422 DOI: 10.1016/j.pnpbp.2022.110642] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 09/14/2022] [Accepted: 09/16/2022] [Indexed: 12/09/2022]
Abstract
Prenatal exposure to maternal immune activation (MIA) and chronic adolescent cannabis use are both risk factors for neuropsychiatric disorders. However, exposure to a single risk factor may not result in major mental illness, indicating that multiple exposures may be required for illness onset. Here, we examine whether combined exposure to prenatal MIA and adolescent delta-9-tetrahydrocannabinol (THC), the main psychoactive component of cannabis, lead to enduring neuroanatomical and behavioural changes in adulthood. Mice were prenatally exposed to viral mimetic, poly I:C (5 mg/kg), or vehicle at gestational day (GD) 9, and postnatally exposed to chronic THC (5 mg/kg, intraperitoneal) or vehicle during adolescence (postnatal day [PND]28-45). Longitudinal magnetic resonance imaging (MRI) was performed pre-treatment, PND 25, post-treatment, PND 50, and in adulthood, PND85, followed by behavioural tests for anxiety-like, social, and sensorimotor gating. Post-mortem assessment of cannabinoid (CB)1 and 2 receptor expressing cells was performed in altered regions identified by MRI (anterior cingulate and somatosensory cortices, striatum, and hippocampus). Subtle deviations in neurodevelopmental trajectory and subthreshold anxiety-like behaviours were observed in mice exposed to both risk factors. Sex-dependent effects were observed in patterns of shared brain-behaviour covariation, indicative of potential sex differences in response to MIA and THC. Density of CB1 and CB2 receptor positive cells was significantly decreased in all mice exposed to MIA, THC, or both. These findings suggest that there may be a cumulative effect of risk factor exposure on gross neuroanatomical development, and that the endocannabinoid system may be sensitive to both prenatal MIA, adolescent THC, or the combination.
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Affiliation(s)
- Elisa Guma
- Computational Brain Anatomy Laboratory, Cerebral Imaging Center, Douglas Mental Health University Institute, Montreal, Quebec, Canada; Integrated Program in Neuroscience, McGill University, Montreal, Quebec, Canada; Developmental Neurogenomics Unit, Human Genetics Branch, National Institute of Mental Health, Bethesda, MD, USA.
| | - Lani Cupo
- Computational Brain Anatomy Laboratory, Cerebral Imaging Center, Douglas Mental Health University Institute, Montreal, Quebec, Canada; Integrated Program in Neuroscience, McGill University, Montreal, Quebec, Canada
| | - Weiya Ma
- Douglas Mental Health University Institute, McGill University, Montréal, Québec, Canada
| | - Daniel Gallino
- Computational Brain Anatomy Laboratory, Cerebral Imaging Center, Douglas Mental Health University Institute, Montreal, Quebec, Canada
| | - Luc Moquin
- Douglas Mental Health University Institute, McGill University, Montréal, Québec, Canada
| | - Alain Gratton
- Integrated Program in Neuroscience, McGill University, Montreal, Quebec, Canada; Department of Psychiatry, McGill University, Montreal, Quebec, Canada; Douglas Mental Health University Institute, McGill University, Montréal, Québec, Canada
| | - Gabriel A Devenyi
- Computational Brain Anatomy Laboratory, Cerebral Imaging Center, Douglas Mental Health University Institute, Montreal, Quebec, Canada; Department of Psychiatry, McGill University, Montreal, Quebec, Canada; Douglas Mental Health University Institute, McGill University, Montréal, Québec, Canada
| | - M Mallar Chakravarty
- Computational Brain Anatomy Laboratory, Cerebral Imaging Center, Douglas Mental Health University Institute, Montreal, Quebec, Canada; Integrated Program in Neuroscience, McGill University, Montreal, Quebec, Canada; Department of Psychiatry, McGill University, Montreal, Quebec, Canada; Douglas Mental Health University Institute, McGill University, Montréal, Québec, Canada; Department of Biological and Biomedical Engineering, McGill University, Montreal, Quebec, Canada.
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Stollenwerk TM, Hillard CJ. Adolescent THC Treatment Does Not Potentiate the Behavioral Effects in Adulthood of Maternal Immune Activation. Cells 2021; 10:3503. [PMID: 34944011 PMCID: PMC8700174 DOI: 10.3390/cells10123503] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/09/2021] [Accepted: 12/10/2021] [Indexed: 02/06/2023] Open
Abstract
Both in utero exposure to maternal immune activation and cannabis use during adolescence have been associated with increased risk for the development of schizophrenia; however, whether these exposures exert synergistic effects on brain function is not known. In the present study, mild maternal immune activation (MIA) was elicited in mice with prenatal exposure to polyinosinic-polycytidylic acid (poly(I:C)), and ∆9-tetrahydrocannabinol (THC) was provided throughout adolescence in cereal (3 mg/kg/day for 5 days). Neither THC nor MIA pretreatments altered activity in assays used to characterize hyperdopaminergic states in adulthood: amphetamine hyperlocomotion and prepulse inhibition of the acoustic startle reflex. Adolescent THC treatment elicited deficits in spatial memory and enhanced spatial reversal learning in adult female mice in the Morris water maze, while exposure to MIA elicited female-specific deficits in fear extinction learning in adulthood. There were no effects in these assays in adult males, nor were there interactions between THC and MIA in adult females. While doses of poly(I:C) and THC were sufficient to elicit behavioral effects, particularly relating to cognitive performance in females, there was no evidence that adolescent THC exposure synergized with the risk imposed by MIA to worsen behavioral outcomes in adult mice of either sex.
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Affiliation(s)
| | - Cecilia J. Hillard
- Neuroscience Research Center, Department of Pharmacology and Toxicology, Medical College of Wisconsin, Wauwatosa, WI 53226, USA;
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