NCT02864680

Electrophysiological Study of the Functioning of Magnocellular Visual Pathway in Regular Cannabis Users

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 163 (actual)
• Sponsor: Central Hospital, Nancy, France · Academic / Other
• Sex: All
• Age: 18 Years – 55 Years
• Healthy volunteers: Accepted

Summary

This study will evaluate the impact of regular use of cannabis on the spatial sensitivity of magnocellular system (visual event-related potential, visual ERP). Secondary purposes of this study are to evaluate the impact of regular use of cannabis on the temporal sensitivity of magnocellular system (visual event-related potential), on the dynamics of cortical visual processing during face perception test (visual event-related potential) and on functioning of retinal photopic and scotopic systems (electroretinogram). The ancillary study is a genetic analysis of a group of candidate genes that aims to identify biomarkers for changes in visual processing. This will allow to distinguish among more homogeneous and specific groups in future studies on larger cannabis user population. This ancillary study concerns all participants subject to their informed consent (facultative study).

Conditions

• Cannabis Use

Interventions

Type	Name	Description
OTHER	Electroretinography
OTHER	Contrast sensitivity test during Electroencephalography	Stimuli are black and white grids, having different range of spatial frequencies, presented with different contrasts on a grey background thanks to a computer monitor, in a dark room. Participants are requested to maintain central fixation. During the test patients stay sit, head hold by chin strap. A pause can be asked by participant and done at every moment. This test lasts approximately 30 minutes.
OTHER	Visual simultaneity test during Electroencephalography	Two vertical bars are showed on a monitor, on the link and right of point of central fixation. Bars appear simultaneously or with a 10 to 200 ms asynchrony. Participants must determine whether stimuli are simultaneous or asynchronous and answer pressing the link button for simultaneity or right button for asynchrony. During the test patients stay sit, head hold by chin strap. A pause can be asked by participant and done at every moment. This test lasts approximately 30 minutes.
OTHER	Face perception test during Electroencephalography	Faces filtered in different spatial frequence ranges are showed randomly on a monitor, in a dark room. Participants must maintain a central fixation thank to a fixation cross. During the test patients stay sit, head hold by chin strap. A pause can be asked by participant and done at every moment. This test lasts approximately 30 minutes.
OTHER	CAST (cannabis abuse screening test)
OTHER	PANSS (Positive And Negative Symptoms Scale) test
OTHER	Delayed Matching to Sample (DMS) test
OTHER	Spatial Working Memory (SWM) test
OTHER	Rapid Visual Information Processing (RVP) test
OTHER	Test for attentional performance (TAP) / Divided Attention
OTHER	Collection of saliva sample	In case of specific consent of participant to ancillary study, for ancillary study

Timeline

• Start date: 2014-02-01
• Primary completion: 2019-06-01
• Completion: 2019-06-01
• First posted: 2016-08-12
• Last updated: 2021-04-29

Locations

1 site across 1 country: France