Effects of Chronic Intake of Cannabis on Contrast Sensitivity

• Sponsor: University Hospital, Strasbourg, France (Other)
• Overall Status: Completed
• CT.gov ID: NCT01793961
• Collaborator: (none)
• Enrollment: 95
• Arms: 3
• Actual Duration (Months): 65.6

Study Details

Study Description

Brief Summary

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.

Condition or Disease	Intervention/Treatment	Phase
Cannabis Dependence	Other: electroretinogram; Other: contrast sensitivity tests	N/A

Study Design

• Study Type: Interventional
• Actual Enrollment: 95 participants
• Allocation: Non-Randomized
• Intervention Model: Parallel Assignment
• Masking: None (Open Label)
• Primary Purpose: Other
• Official Title: Effects of Chronic Intake of Cannabis on Contrast Sensitivity
• Actual Study Start Date: Mar 22, 2013
• Actual Primary Completion Date: Nov 30, 2015
• Actual Study Completion Date: Sep 10, 2018

Arms and Interventions

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

Outcome Measures

Primary Outcome Measures

1. The contrast detection treshold [up to 9 days after inclusion]

   Comparison of the contrast detection threshold of the 3 groups

Eligibility Criteria

Criteria

• Ages Eligible for Study: 18 Years to 50 Years
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: Yes

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

Contacts and Locations

Locations

No locations specified.

Sponsors and Collaborators

• University Hospital, Strasbourg, France

Investigators

None specified.

Study Documents (Full-Text)

None provided.

More Information

Publications

None provided.

• Responsible Party: University Hospital, Strasbourg, France
• ClinicalTrials.gov Identifier: NCT01793961
• Other Study ID Numbers: 5331; 2012-A00991-42
• First Posted: Feb 18, 2013
• Last Update Posted: Jul 12, 2019
• Last Verified: Jul 1, 2019

• Additional relevant MeSH terms: Marijuana Abuse

Study Results

No Results Posted as of Jul 12, 2019