Dataset Information

Investigating the causal effect of cannabis use on cognitive function with a quasi-experimental co-twin design.

ABSTRACT:

Background

It is unclear whether cannabis use causes cognitive decline; several studies show an association between cannabis use and cognitive decline, but quasi-experimental twin studies have found little support for a causal effect. Here, we evaluate the association of cannabis use with general cognitive ability and executive functions (EFs) while controlling for genetic and shared environmental confounds in a longitudinal twin study.

Methods

We first examined the phenotypic associations between cannabis initiation, frequency, and use disorder with cognitive abilities, while also controlling for pre-use general cognitive ability and other substance involvement. We tested the concurrent association between the cannabis use variables and cognitive abilities in late adolescence and young adulthood and the longitudinal association between cannabis use variables during adolescence and young adulthood cognitive abilities. Next, we used multilevel models to test whether these relations reflect between- and/or within-twin pair associations.

Results

Phenotypically, cannabis use was related to poorer cognitive functioning, although most associations were negligible after accounting for other substance use. Nevertheless, there were few significant within-family twin-specific associations, except that age 17 cannabis frequency was associated with worse age 23 Common EF and general cognitive ability.

Conclusions

We found little support for a potential causal effect of cannabis use on cognition, consistent with previous twin studies. Results suggest that cannabis use may not cause decline in cognitive ability among a normative sample of cannabis users.

SUBMITTER: Ross JM

PROVIDER: S-EPMC7179798 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature

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Publications

Investigating the causal effect of cannabis use on cognitive function with a quasi-experimental co-twin design.

Ross J Megan JM Ellingson Jarrod M JM Rhee Soo Hyun SH Hewitt John K JK Corley Robin P RP Lessem Jeffrey M JM Friedman Naomi P NP

Drug and alcohol dependence 20191102

<h4>Background</h4>It is unclear whether cannabis use causes cognitive decline; several studies show an association between cannabis use and cognitive decline, but quasi-experimental twin studies have found little support for a causal effect. Here, we evaluate the association of cannabis use with general cognitive ability and executive functions (EFs) while controlling for genetic and shared environmental confounds in a longitudinal twin study.<h4>Methods</h4>We first examined the phenotypic ass ...[more]

PMID: 31753729

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Project description:AIMS:This study tested whether adolescents who used cannabis or met criteria for cannabis dependence showed neuropsychological impairment prior to cannabis initiation and neuropsychological decline from before to after cannabis initiation. DESIGN:A longitudinal co-twin control study. SETTING AND PARTICIPANTS:Participants were 1989 twins from the Environmental Risk (E-Risk) Longitudinal Twin Study, a nationally representative birth cohort of twins born in England and Wales from 1994 to 1995. MEASUREMENTS:Frequency of cannabis use and cannabis dependence were assessed at age 18. Intelligence quotient (IQ) was obtained at ages 5, 12 and 18. Executive functions were assessed at age 18. FINDINGS:Compared with adolescents who did not use cannabis, adolescents who used cannabis had lower IQ in childhood prior to cannabis initiation and lower IQ at age 18, but there was little evidence that cannabis use was associated with IQ decline from ages 12-18. For example, adolescents with cannabis dependence had age 12 and age 18 IQ scores that were 5.61 (t = -3.11, P = 0.002) and 7.34 IQ points (t = -5.27, P < 0.001) lower than adolescents without cannabis dependence, but adolescents with cannabis dependence did not show greater IQ decline from age 12-18 (t = -1.27, P = 0.20). Moreover, adolescents who used cannabis had poorer executive functions at age 18 than adolescents who did not use cannabis, but these associations were generally not apparent within twin pairs. For example, twins who used cannabis more frequently than their co-twin performed similarly to their co-twin on five of six executive function tests (Ps > 0.10). The one exception was that twins who used cannabis more frequently than their co-twin performed worse on one working memory test (Spatial Span reversed; ? = -0.07, P = 0.036). CONCLUSIONS:Short-term cannabis use in adolescence does not appear to cause IQ decline or impair executive functions, even when cannabis use reaches the level of dependence. Family background factors explain why adolescent cannabis users perform worse on IQ and executive function tests.

Project description:AimsTo estimate the effect of recreational legalization on cannabis use frequency and sources of variance across legal environments.DesignLongitudinal discordant twin and gene-environment interaction models in twins recruited from birth records and assessed prospectively.SettingThe United States, including states with different recreational cannabis policies before and after 2014, when recreational cannabis was first legalized.ParticipantsTwo longitudinal, prospectively assessed samples of American twins aged 24-47 (n = 1425 in legal states, n = 1996 in illegal states), including 111 monozygotic pairs discordant for residence.MeasurementsCurrent cannabis use frequency (measured continuously and ordinally) was the primary outcome, and the predictor was recreational status of cannabis (legal/illegal) in the participant's state of residence at the time of assessment. Covariates include age, sex and cannabis use frequency prior to 2014.FindingsAccounting for pre-2014 use, residents of legal states used cannabis more frequently than residents of illegal states (b = 0.21, P = 8.08 × 10-5 ). Comparing 111 pairs of monozygotic twins discordant for residence confirmed the effect (b = 0.18, P = 0.014). There was inconclusive evidence for genetic influences on cannabis use frequency that were specific to the legal environment [χ2 = 2.9 × 10-9 , degrees of freedom (d.f.) = 1, P > 0.999]. Existing genetic influences were moderated by the legal environment, as the genetic correlation between marijuana use before and after legalization was lower in states that legalized (rgenetic = 0.24) compared with states that did not (rgenetic = 0.78, Pdifference = 0.016).ConclusionsIn the United States, there appears to be a ~ 20% average increase in cannabis use frequency attributable to recreational legalization, consistent across increasingly rigorous designs. In addition, the heritability of cannabis use frequency appears to be moderated by legalization.

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Project description:BackgroundVideo-based teaching has been part of medical education for some time but 360° videos using a virtual reality (VR) device are a new medium that offer extended possibilities. We investigated whether adding a 360° VR video to the internship curriculum leads to an improvement of long-term recall of specific knowledge on a gentle Caesarean Sections (gCS) and on general obstetric knowledge.MethodsTwo weeks prior to their Obstetrics and Gynaecology (O&G) internship, medical students were divided in teaching groups, that did or did not have access to a VR-video of a gCS. Six weeks after their O&G internship, potentially having observed one or multiple real-life CSs, knowledge on the gCS was assessed with an open questionnaire, and knowledge on general obstetrics with a multiple-choice questionnaire. Furthermore we assessed experienced anxiety during in-person attendance of CSs, and we asked whether the interns would have wanted to attend more CSs in-person. The 360° VR video group was questioned about their experience directly after they watched the video. We used linear regression analyses to determine significant effects on outcomes.ResultsA total of 89 medical students participated, 41 in the 360° VR video group and 48 in the conventional study group. Watching the 360° VR video did not result in a difference in either specific or general knowledge retention between the intervention group and the conventional study group. This was both true for the grade received for the internship, the open-ended questions as well as the multiple-choice questions and this did not change after adjustment for confounding factors. Still, 83.4% of the 360° VR video-group reported that more videos should be used in training to prepare for surgical procedures. In the 360° VR video-group 56.7% reported side effects like nausea or dizziness. After adjustment for the number of attended CSs during the practical internship, students in the 360° VR video-group stated less often (p = 0.04) that they would have liked to attend more CSs in-person as compared to the conventional study group.ConclusionEven though the use of 360° VR video did not increase knowledge, it did offer a potential alternative for attending a CS in-person and a new way to prepare the students for their first operating room experiences.

Dataset Information

Investigating the causal effect of cannabis use on cognitive function with a quasi-experimental co-twin design.

Background

Methods

Results

Conclusions

Publications

Investigating the causal effect of cannabis use on cognitive function with a quasi-experimental co-twin design.

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