Cannabis Use
Conditions
Keywords
cannabis, magnocellular pathway
Brief 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).
Interventions
OTHERElectroretinography
OTHERContrast 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.
OTHERVisual 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.
OTHERFace 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.
OTHERCAST (cannabis abuse screening test)
OTHERPANSS (Positive And Negative Symptoms Scale) test
OTHERDelayed Matching to Sample (DMS) test
OTHERSpatial Working Memory (SWM) test
OTHERRapid Visual Information Processing (RVP) test
OTHERTest for attentional performance (TAP) / Divided Attention
OTHERCollection of saliva sample
In case of specific consent of participant to ancillary study, for ancillary study
Sponsors
Central Hospital, Nancy, France
Study design
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
OTHER
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 55 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Culmination time of the P100 wave in contrast sensibility test | up to 1 month |
| Amplitude of P100 wave in contrast sensibility test | up to 1 month |
Secondary
| Measure | Time frame |
|---|---|
| Culmination time of P100 wave in visual simultaneity test | up to 1 month |
| Amplitude of P100 wave in face perception test | up to 1 month |
| Amplitude of N170 wave in face perception test | up to 1 month |
| Culmination time of P100 wave in face perception test | up to 1 month |
| Amplitude of a wave in different ERG sequences | day 0 |
| Amplitude of b wave in different ERG sequences | day 0 |
| Culmination time of a wave in different ERG sequences | day 0 |
| Culmination time of b wave in different ERG sequences | day 0 |
| Culmination time of N170 wave in face perception test | up to 1 month |
| Amplitude of P100 wave in visual simultaneity test | up to 1 month |
Other
| Measure | Time frame |
|---|---|
| Relationship between variants of candidate genes for alterations of visual treatment and amplitude of P100 wave in contrast sensibility test | up to 3 years |
Countries
France
Outcome results
None listed