A systematic review of oculomotor deficits associated with acute and chronic cannabis use

Abstract

Driving is a critical everyday task necessitating the rapid and seamless integration of dynamic visually derived information to guide neurobehaviour. Biological markers are frequently employed to detect Δ9‐tetrahydrocannabinol (THC) consumption among drivers during roadside tests, despite not necessarily indicating impairment. Characterising THC‐specific alterations to oculomotor behaviour may offer a more sensitive measure for indexing drug‐related impairment, necessitating discrimination between acute THC effects, chronic use and potential tolerance effects. The present review aims to synthesise current evidence on the acute and chronic effects of THC on driving‐relevant oculomotor behaviour. The review was prospectively registered (10.17605/OSF.IO/A4H9W), and Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines informed reporting standards. Overall, 20 included articles comprising 12 experimental acute dosing trials, 5 cross‐sectional chronic use studies and 3 roadside epidemiological studies examined the effects of cannabis/THC on oculomotor parameters including saccadic activity gaze behaviour, nystagmus, smooth pursuit and eyelid/blink characteristics. Acute THC consumption selectively impacts oculomotor control, notably increasing saccadic latency and inaccuracy and impairing inhibitory control. Chronic cannabis users, especially those with early age of use onset, display enduring oculomotor deficits that affect visual scanning efficiency. The presence of eyelid tremors appears to be a reliable indicator of cannabis consumption while remaining distinct from direct impairment associated with visual attention and motor control. Cannabis selectively influences oculomotor activity relevant to driving, highlighting the role of cannabinoid systems in these processes. Defining cannabis/THC‐specific changes in oculomotor control may enhance the precision of roadside impairment assessments and vehicle safety systems to detect drug‐related impairment and assess driving fitness.

A Study of Pupil Response to Light as a Digital Biomarker of Recent Cannabis Use

“…In addition, it would have been valuable to examine the pupillary light response closer in time to smoking, and at a longer time interval following use to examine how the response changes over time. Other metrics of oculomotor deficits, such as saccadic accuracy and eyelid tremors, showed consistent evidence of acute cannabis use [11]; however, these metrics were not available for analysis in this study. Under these constraints, the utility of the derived model to discriminate recent cannabis use from no use assessed by AUC of the ROC plot yielded a value of approximately 0.7 (Fig.…”

“…Some measures, such as saccadic accuracy, fixation duration, fixation rate, and visual regression, have consistent effects across studies, while others such as vertical and horizontal nystagmus are not reliably reproduced or depend on the administered test [11]. This review indicates that these measures may vary with frequency of cannabis use, and future studies should focus on a broad spectrum of consumption patterns [11]. Given the limitations of blood THC levels and existing roadside assessments, there is a need for the development of objective markers of recent cannabis use.…”

“…This is due to the fact that frequent users can maintain elevated levels of blood THC for weeks after consumption; as such, frequent cannabis users may have a positive blood test for THC even if they have not recently smoked cannabis [10]. In a recent systematic review by Manning et al [11], the authors reviewed studies of a variety of oculomotor measures used in roadside safety tests and vehicle safety systems. Some measures, such as saccadic accuracy, fixation duration, fixation rate, and visual regression, have consistent effects across studies, while others such as vertical and horizontal nystagmus are not reliably reproduced or depend on the administered test [11].…”

“…In a recent systematic review by Manning et al [11], the authors reviewed studies of a variety of oculomotor measures used in roadside safety tests and vehicle safety systems. Some measures, such as saccadic accuracy, fixation duration, fixation rate, and visual regression, have consistent effects across studies, while others such as vertical and horizontal nystagmus are not reliably reproduced or depend on the administered test [11]. This review indicates that these measures may vary with frequency of cannabis use, and future studies should focus on a broad spectrum of consumption patterns [11].…”

Cannabisprävention in der Schule: Ergebnisse einer cluster-randomisierten Studie

“…Der regelmäßige Cannabiskonsum im Jugendalter ist besonders besorgniserregend, da der Konsum in dieser Altersgruppe mit einer erhöhten Wahrscheinlichkeit schädlicher kurz-und langfristiger Folgenverbundenist [5].ZudenkurzfristigenAuswirkungendes Konsums gehören eine Beeinträchtigung des Kurzzeitgedächtnisses [6],zunehmendeSchwierigkeitenbeimLernenundBehalten von Informationen, Beeinträchtigung der motorischen Koordination, Beeinträchtigung der Fahrtüchtigkeit und Erhöhung des Verletzungsrisikos [7],verändertesUrteilsvermögensowieerhöhtes Risiko für sexuell riskantes Verhalten, das die Infektion mit sexuell übertragbarenKrankheitenerleichtert [8].Langanhaltenderoder starker Konsum im Jugendalter können zu einer Abhängigkeit führen [9],zueinerverändertenGehirnentwicklung [10],schlechten Bildungsergebnissen [11],miterhöhterWahrscheinlichkeiteines SchulabbruchsundgeringeremberuflichenErfolg.Fernerkönnen Symptome einer chronischen Bronchitis und verminderte Lebenszufriedenheit auftreten. Kognitive Beeinträchtigungen und ein erhöhtes Risiko für psychische Probleme einschließlich chronischer psychotischer Störungen sind mit dem Cannabiskonsum assoziiert [12,13,14].…”