Examining tDCS Effect on Cannabis Use Disorder in Patients With Schizophrenia

Study Overview
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Brief Summary
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Cannabis use disorder is a frequent comorbidity of schizophrenia, associated with increased symptoms and less adherence to therapy. Validated care has limited effectiveness in this population and development of new management strategies seems necessary. Transcranial direct current stimulation (tDCS) has shown beneficial effects in both schizophrenia, substance use disorder and, in a less extent, in nicotine addiction in schizophrenic subjects. It is interesting to test if that 10 sessions of anodal stimulation of the right dorsolateral prefrontal cortex (DLPFC) and cathodal stimulation of the medial prefrontal cortex (MPFC) (by increasing control and modulating reward system), will reduce, in 110 schizophrenic subjects, cannabis consumption, and secondly craving, addiction severity, schizophrenic symptoms and improve global functioning. It is possible that these clinical effects will be associated with changes in certain cognitive functions and cerebral connectivity.

Detailed Description
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Stimulation will be performed using a Neurocan DC-Stimulator Plus with two 7×5 cm sponge electrodes soaked in a saline solution. Electrodes will be placed in accordance with the international 10-20 electrode placement system: the anode over F4 (right DLPFC), the cathode over Fp1 (MPFC). The stimulation level will be set at 2 mA for 20 minutes during stimulation sessions twice a day (separated by at least 3 hours) for 5 consecutive weekdays. The control group will receive the sham stimulation following the same regimen, using the sham procedure which has been developed by the manufacturer of the tDCS material, allowing sensations to be felt in the scalp which are the equivalent to those of the active stimulation. The same device will be used for both the sham and the active procedures.

Official Title
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Examining tDCS Effect on Cannabis Use Disorder in Patients With Schizophrenia A Randomized Controlled Double-blind Exploratory Multicentric Study

Conditions
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Schizophrenia, Cannabis-Induced Disorder

Intervention / Treatment
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* Device: Transcranial direct current stimulation (tDCS) active
* Device: Transcranial direct current stimulation (tDCS) non active


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Schizophrenia diagnostic according to DSM (Diagnostic and Statistical Manual of mental disorder) 5 criteria, without change in psychotropic treatment since at least 4 weeks Moderate to severe cannabis use disorder according to DSM 5 criteria and active consumption during the last 7 days Subjects motivated to reduce or quit their cannabis consumption Patients with ambulatory compulsory care may be included Exclusion Criteria: Other substance use disorder, excluding nicotine, according to DSM 5 criteria Other current psychiatric disorder according to DSM 5 criteria, excluding personality disorder Inpatient hospitalization History of head injury, neurological disorder with cerebral consequence or severe unstable somatic disorder Pregnancy or no contraception Contraindications for tDCS and/or MRI (implanted material, uncontrolled epilepsy, intracranial hypertension)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Stimulation will be performed using a Neurocan DC-Stimulator Plus with two 7×5 cm sponge electrodes soaked in a saline solution. Electrodes will be placed in accordance with the international 10-20 electrode placement system: the anode over F4 (right DLPFC), the cathode over Fp1 (MPFC). The stimulation level will be set at 2 mA for 20 minutes during stimulation sessions twice a day (separated by at least 3 hours) for 5 consecutive weekdays. The control group will receive the sham stimulation following the same regimen, using the sham procedure which has been developed by the manufacturer of the tDCS material, allowing sensations to be felt in the scalp which are the equivalent to those of the active stimulation. The same device will be used for both the sham and the active procedures.
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: active tDCS stimulation<br>Transcranial direct current stimulation tDCS-Stimulation will be performed using a Neurocan DC-Stimulator Plus | Device: Transcranial direct current stimulation (tDCS) active<br>* Stimulation will be performed using a Neurocan DC-Stimulator Plus with two 7×5 cm sponge electrodes soaked in a saline solution. Electrodes will be placed in accordance with the international 10-20 electrode placement system: the anode over F4 (right DLPFC), the cathode over Fp1 (MPFC). The stimulation level will be set at 2 mA for 20 minutes during stimulation sessions twice a day (separated by at least 3 hours) for 5 consecutive weekdays.<br>|
| Sham Comparator: sham tDCS stimulation<br>Transcranial direct current stimulation tDCS-The control group will receive the sham stimulation following the same regimen, using the sham procedure . | Device: Transcranial direct current stimulation (tDCS) non active<br>* The control group will receive the sham stimulation following the same regimen, using the sham procedure which has been developed by the manufacturer of the tDCS material, allowing sensations to be felt in the scalp which are the equivalent to those of the active stimulation. The same device will be used for both the sham and the active procedures.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| cannabis use | Percentage change in cannabis use before and after tDCS treatment | 6 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| cannabis use | Percentage change in cannabis use before and after 3 months tDCS treatment | 3 months | 
| Change in craving scores | Marijuana Craving Questionnaire score (minimum =12, maximum = 84). The higher the score, the greater the craving. | 3 months and 6 months | 
| Hospitalizations | Number of hospitalization(s) during the 6 months after tDCS sessions | 6 months | 
| Study of structural cerebral connectivity | Cerebral MRI (only for a subgroup of patients) : Diffusion of water at the white matter level for the evaluation of structural brain connectivity in DTI mode (diffusion tensor) on | 3 months | 
| Study of structural and functional cerebral connectivity | Cerebral MRI (only for a subgroup of patients) : Functional connectivity index evaluated by resting state default mode network (MRI) for the evaluation of functional brain connectivity | 3 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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dorsolateral prefrontal cortex, medial prefrontal cortex, schizophrenia, cannabis-induced disorder