Contrast sensitivity and motion discrimination in cannabis users

Elena, María

doi:10.1007/s00213-018-4944-2

Cited by 16 publications

(15 citation statements)

References 51 publications

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“…Lalanne et al 18 revealed that CS is permanently altered in cannabis users with an early onset, especially for lower frequencies. Other work has found a reduction in CS in abstaining cannabis users in low light 19 , but not in higher light conditions 45 .…”

Section: Discussionmentioning

confidence: 82%

“…Cannabis intoxication also seems to impair visual processing, with effects including a reduction in the binocular depth inversion illusion, which occurs when a three-dimensional object is presented pseudoscopically 15 . This effect is also noted in long-term users 16 , as are other effects related to a slowing down of visual information processing, such as dysfunction in the ganglion cells 17 , reduced contrast sensitivity 18,19 , impaired motion perception 19,20 and a drop in the quality of reading-related ocular movements 21 . In contrast, other observationbased or case study work has argued that acute cannabis intoxication exerts positive effects on nighttime vision, with improved adaptation to darkness and scotopic sensitivity 22,23 .…”

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confidence: 88%

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Effects of cannabis on visual function and self-perceived visual quality

Ortiz-Peregrina

Ortíz

Casares-López

et al. 2021

Sci Rep

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Cannabis is one of the most used drugs of abuse in the world. The objective of this study was to analyze the effects of smoking cannabis on vision and to relate these to those perceived by the user. Thirty-one cannabis users participated in this study. Visual function assessment was carried out in a baseline session as well as after smoking cannabis. We evaluated static visual acuity, contrast sensitivity, stereoacuity, accommodative response, straylight, night-vision disturbances (halos) and pupil size. The participants were also divided into two groups depending on whether they perceived their vision to have worsened after smoking cannabis. A logistic regression analysis was employed to identify which visual test could best predict self-perceived visual effects. The study found that smoking cannabis has significant adverse effects on all the visual parameters analyzed (p < 0.05). Self-perceived visual quality results revealed that about two thirds of the sample think that smoking cannabis impairs their vision. Contrast sensitivity, specifically for the spatial frequency 18 cpd, was identified as the only visual parameter significantly associated with self-perceived visual quality (Odds Ratio: 1.135; p = 0.040). Smoking cannabis is associated with negative effects on visual function. Self-perceived visual quality after smoking cannabis could be related to impaired contrast sensitivity.

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Section: Discussionmentioning

confidence: 82%

mentioning

confidence: 88%

Effects of cannabis on visual function and self-perceived visual quality

Ortiz-Peregrina

Ortíz

Casares-López

et al. 2021

Sci Rep

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“…Measures. Taking *2 min, the DRUID mobile app assesses psychomotor and cognitive impairment by having users complete four tasks that call upon several capabilities potentially affected by cannabis: eyes-open balance, reaction time, and performance on a psychomotor vigilance task, 25 hand-eye coordination, 26 attention to motion stimuli, 27 and time estimation. 28 DRUID integrates task-level intermediate variables by using a proprietary algorithm to produce a total impairment score, our primary outcome measure.…”

Section: Colorado Studymentioning

confidence: 99%

Effects of High-Potency Cannabis on Psychomotor Performance in Frequent Cannabis Users

Karoly

Milburn²,

Brooks‐Russell

et al. 2022

Cannabis and Cannabinoid Research

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Background: Recently increased access to cannabis products in the United States has been associated with increased rates of driving after cannabis use. Although numerous studies indicate that cannabis impairs psychomotor and neurocognitive functions that can affect driving ability, the determination of cannabis-impaired driving risk is complicated by the extent to which frequent cannabis users develop tolerance to THC's subjective, cognitive, and psychomotor effects, and by the fact that there is no validated behavioral or biological marker of recent cannabis use or cannabis-related impairment. This study examined the psychomotor impairment-related effects experienced by frequent cannabis users in Colorado after naturalistic consumption of smoked cannabis, both immediately and 1 h postuse. Results were then validated in a smaller replication sample from Washington state. Methods: In the primary Colorado study, participants (n = 70) used the DRUID Ò mobile app, a brief measure of psychomotor and cognitive domains that are sensitive to the effects of cannabis. First, participants used DRUID to establish a sober baseline impairment score. During a second appointment, they used DRUID at three time points: preuse, immediately after acutely using cannabis, and 1 h postuse. In the Washington replication sample, participants (n = 39) used DRUID before acute cannabis consumption and then every half hour for 2.5 h. Results: In both studies, peak DRUID impairment effects were seen immediately after cannabis use, with recovery of performance at 1 h postuse. Specifically, significant quadratic effects of time emerged for both studies (Colorado study: (b = À0.935, SE = 0.204, p < 0.001); Washington study: b = 3.0299, SE = 1.3085, p < 0.01). Domain-specific effects were tested in the larger Colorado study and were observed for reaction time within a complex divided attention task and a postural-stability balance task. Conclusions: These findings demonstrate that psychomotor impairment emerges immediately after acute cannabis use even in regular users, but decreases significantly 1 h postuse. These results underscore the potential utility of the DRUID app for assessing acute cannabis-related psychomotor impairment. Further research is needed to explore whether the DRUID app and/or the specific psychomotor functions it assesses might serve as a tool for measuring cannabis-related driving impairment. Clinical trials registration number for the Colorado Study: NCT03522103.

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“…On the DRUID ® , participants performed four 30–45 s tasks, which measured reaction time, decision-making, hand-eye coordination, and time estimation under conditions of divided attention as well as a balance task (Richman and May, 2019). These performance domains are the most reliable predictors of driving impairment caused by cannabis and alcohol (Jongen et al, 2014; Mikulskaya and Martin, 2018). On Task 1, shapes (either a square or circle) flashed on the screen; one shape was designated as the target shape and the other the control shape.…”

Section: Methodsmentioning

confidence: 99%

Assessment of cognitive and psychomotor impairment, subjective effects, and blood THC concentrations following acute administration of oral and vaporized cannabis

et al. 2021

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Background: Cannabis legalization is expanding, but there are no established methods for detecting cannabis impairment. Aim: Characterize the acute impairing effects of oral and vaporized cannabis using various performance tests. Methods: Participants ( N = 20, 10 men/10 women) who were infrequent cannabis users ingested cannabis brownies (0, 10, and 25 mg Δ-9-tetrahydrocannabinol, THC) and inhaled vaporized cannabis (0, 5, and 20 mg THC) in six double-blind outpatient sessions. Cognitive/psychomotor impairment was assessed with a battery of computerized tasks sensitive to cannabis effects, a novel test (the DRiving Under the Influence of Drugs, DRUID®), and field sobriety tests. Blood THC concentrations and subjective drug effects were evaluated. Results: Low oral/vaporized doses did not impair cognitive/psychomotor performance relative to placebo but produced positive subjective effects. High oral/vaporized doses impaired cognitive/psychomotor performance and increased positive and negative subjective effects. The DRUID® was the most sensitive test to cannabis impairment, as it detected significant differences between placebo and active doses within both routes of administration. Women displayed more impairment on the DRUID® than men at the high vaporized dose only. Field sobriety tests showed little sensitivity to cannabis-induced impairment. Blood THC concentrations were far lower after cannabis ingestion versus inhalation. After inhalation, blood THC concentrations typically returned to baseline well before pharmacodynamic effects subsided. Conclusions: Standard approaches for identifying impairment due to cannabis exposure (i.e. blood THC and field sobriety tests) have severe limitations. There is a need to identify novel biomarkers of cannabis exposure and/or behavioral tests like the DRUID® that can reliably and accurately detect cannabis impairment at the roadside and in the workplace.

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Contrast sensitivity and motion discrimination in cannabis users

Cited by 16 publications

References 51 publications

Effects of cannabis on visual function and self-perceived visual quality

Effects of cannabis on visual function and self-perceived visual quality

Effects of High-Potency Cannabis on Psychomotor Performance in Frequent Cannabis Users

Assessment of cognitive and psychomotor impairment, subjective effects, and blood THC concentrations following acute administration of oral and vaporized cannabis

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