Effects of Chronic Intake of Cannabis on Contrast Sensitivity

July 10, 2019 updated by: University Hospital, Strasbourg, France

Rates of driving under the influence of cannabis have risen in recent years. Cannabis is involved in 1/3 of motor vehicle collisions. The chronic use of cannabis is known to affect dopaminergic regulation and may thus impair contrast sensitivity. In turn, contrast sensitivity disorders could originate difficulties to anticipate and avoid collision with objects, especially when objects are in movement. The investigators goal is to examine the effects of a chronic intake of cannabis on contrast sensitivity. The observed values will be compared to standard references. In addition, since smoking cannabis is always associated with tobacco, the investigators will control the effects of tobacco on contrast sensitivity.

In this study, the investigators will include 36 cannabis addicts, 36 tobacco addicts and 36 no smokers. The investigators will present gratings with different spatial frequencies and the investigators will determine contrast thresholds for static and dynamic (moving) gratings. The investigators predict that cannabis addicts will present abnormal contrast sensitivity especially in case of dynamic presentation of gradings.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

95

Phase

  • Not Applicable

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 50 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

"Cannabis" Arm

  • patient addicted to cannabis
  • Positive CAST test result
  • Urine tested positive for cannabis metabolites

"Tobacco" Arm

  • positive Fagerström test result
  • No cannabis intake in the last year before inclusion
  • No previous history of cannabis use

"Healthy Volunteers"

  • No tobacco or cannabis intake in the last year before inclusion
  • No history of addictive disorders

Exclusion Criteria:

  • addiction to other substances than cannabis or tobacco
  • benzodiazepine treatment
  • patient with history of benzodiazepine treatment
  • patient with history of general anesthesia in the last 3 months before inclusion
  • patient with history of head trauma
  • Pregnant woman
  • breast feeding woman
  • Adults under supervision or guardianship

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: "Cannabis" Arm
patient addicted to cannabis
Other: electroretinogram
Other: contrast sensitivity tests
Other: "Tobacco" Arm
patient addicted to tobacco
Other: electroretinogram
Other: contrast sensitivity tests
Other: "Healthy volunteers"
no smokers
Other: electroretinogram
Other: contrast sensitivity tests

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
The contrast detection treshold
Time Frame: up to 9 days after inclusion
Comparison of the contrast detection threshold of the 3 groups
up to 9 days after inclusion

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University Hospital, Strasbourg, France

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 22, 2013

Primary Completion (Actual)

November 30, 2015

Study Completion (Actual)

September 10, 2018

Study Registration Dates

First Submitted

February 12, 2013

First Submitted That Met QC Criteria

February 15, 2013

First Posted (Estimate)

February 18, 2013

Study Record Updates

Last Update Posted (Actual)

July 12, 2019

Last Update Submitted That Met QC Criteria

July 10, 2019

Last Verified

July 1, 2019

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 5331
  • 2012-A00991-42 (Other Identifier: n° IDRCB)

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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