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)