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

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

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

Sponsors & Collaborators

• Central Hospital, Nancy, France

  lead OTHER

Principal Investigators

• Vincent LAPREVOTE · Maison des Addictions - CHU de Nancy, France

Study Design

Allocation

NON_RANDOMIZED

Purpose

OTHER

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

55 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2014-02-28

Primary Completion

2019-06-30

Completion

2019-06-30

Countries

• France

Study Locations