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Completed

NCT Number: NCT02864680

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

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).

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Key information

Conditions

Cannabis Use Chemically-Induced Disorders Marijuana Abuse Mental Disorders Substance-Related Disorders

Age range

18 year–55 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Maison des Addictions - CHU de Nancy, Hôpital St Julien

Nancy, France

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Affiliation to social security plan
  • Normal visual acuity or adjusted to normal and normal dilated fundus examination
  • Signature of informed consent
  • Cannabis user group: More than 7 cannabis uses per week during the previous month
  • Cannabis user group: Positive urinary analysis for presence of cannabis
  • Healthy, non user control group: Absence of cannabis and tobacco use during last 12 months
  • Healthy, non user control group: Negative urinary analysis for presence of cannabis
  • Healthy, non user control group: Age and sex matching with cannabis user group
  • Healthy, tobacco user control group: Tobacco use from at least 12 months
  • Healthy, tobacco user control group: Low to very strong addiction to tobacco (Fagerström test)
  • Healthy, tobacco user control group: Absence of cannabis use from more than 12 months
  • Healthy, tobacco user control group: Negative urinary analysis for presence of cannabis
  • Healthy, tobacco user control group:Age and sex matching with cannabis user group
  • Schizophrenia patient control group: Schizophrenia according to DMS IV criteria (MINI test)
  • Schizophrenia patient control group: Absence of cannabis use from more than one month (regardless of tobacco use)
  • Schizophrenia patient control group: Negative urinary analysis for presence of cannabis
  • Schizophrenia patient control group: Age and sex matching with cannabis user group

Exclusion criteria

  • Acute psychiatric pathology (axis I of DSM IV, measured by MINI) except anxiety disorder (except schizophrenia group)
  • Deficiency of the subject making difficult or impossible his/her participation to the study or the comprehension of the information
  • Dyslexia
  • Addiction to alcohol according to AUDIT scale
  • Abuse or addiction to other substances according to DSM IV criteria
  • Acute retinal disorder
  • Chronic glaucoma
  • Ophthalmic pathology affecting visual acuity
  • Current ocular infection
  • Persons under guardianship, curatorship or judicial protection
  • Pregnant or breast-feeding women
  • Persons with life-and-death emergency
  • Absence of social security plan
  • Results of preliminary medical examinations incompatible with the study
  • Simultaneous participation to another therapeutic interventional study

Treatment and study plan

Electroretinography

Other

Contrast sensitivity test during Electroencephalography

Other

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.

Visual simultaneity test during Electroencephalography

Other

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.

Face perception test during Electroencephalography

Other

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.

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

Other

In case of specific consent of participant to ancillary study, for ancillary study

Primary outcomes

  1. Amplitude of P100 wave in contrast sensibility test

    Time frame: up to 1 month

  2. Culmination time of the P100 wave in contrast sensibility test

    Time frame: up to 1 month

Secondary outcomes

  1. Amplitude of P100 wave in visual simultaneity test

    Time frame: up to 1 month

  2. Culmination time of P100 wave in visual simultaneity test

    Time frame: up to 1 month

  3. Amplitude of P100 wave in face perception test

    Time frame: up to 1 month

  4. Amplitude of N170 wave in face perception test

    Time frame: up to 1 month

  5. Culmination time of P100 wave in face perception test

    Time frame: up to 1 month

  6. Culmination time of N170 wave in face perception test

    Time frame: up to 1 month

  7. Amplitude of "a" wave in different ERG sequences

    Time frame: day 0

  8. Amplitude of "b" wave in different ERG sequences

    Time frame: day 0

  9. Culmination time of "a" wave in different ERG sequences

    Time frame: day 0

  10. Culmination time of "b" wave in different ERG sequences

    Time frame: day 0

Other outcomes

  1. Relationship between variants of candidate genes for alterations of visual treatment and amplitude of P100 wave in contrast sensibility test

    Time frame: up to 3 years

Sponsors and collaborators

Lead sponsor

Central Hospital, Nancy, France

Other

Registry information

Acronym: CAUSA MAP

Important dates

Study start
2014
Primary completion
2019
Study completion
2019
First posted
Aug 12, 2016
Registry last updated
Apr 29, 2021

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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