Effectiveness of tDCS on Reducing Craving in Patients Practicing Chemsex: a Single-center, Double-blind, Randomized Controlled Pilot Trial

Inclusion Criteria:

• Patient who provides written consent

• Patient aged ≥ 18 years

• Patient motivated and willing to change chemsex behavior, assessed by examinerduring screening and inclusion visits

• Patient using at least one of the following psychoactive substances to modify sexualperformance and/or experience:

• Cathinones, or methamphetamine, or MDMA, or cocaine, or ketamine, or GBL/GHB

• ≥ 1 time per month over the past 6 months and/or ≥ 10 times over the past year

Exclusion Criteria:

• Patient with a substance use disorder not involved in the practice of chemsex

• Patient with a recent change (< 1 month) in the prescription of a psychotropictreatment

• Patient presenting an acute psychiatric condition requiring hospitalization and/orimmediate modification of a psychotropic treatment

• Patients with unstable or uncontrolled neuropsychiatric disease

• Patients with a history of epileptic seizures

• Patients with unexplained episodes of loss of consciousness, as this condition maybe linked to cerebral alterations or epilepsy

• Patients with advanced or decompensated somatic pathology, requiring hospitalizationexpected during study follow-up

• Patients suffering from any serious life-threatening illness, such as congestiveheart failure, chronic obstructive pulmonary disease or active neoplasia

• Patients with implanted cerebral medical devices, implanted pacemakers, or anyelectrically, magnetically or mechanically activated implant.

• Patients with cardiac, neural or drug implants

• Patients with vascular clips or other electrically sensitive support systems in thebrain

• Patients with severe brain lesions

• Patients with skin lesions at stimulation sites

• Patients with skin problems such as dermatitis, psoriasis or eczema

• Patients with severe or frequent headaches

• Patients who have already benefited from tDCS sessions

• Pregnant, parturient or breast-feeding women (pregnancy test)

• Staff working in the addictology department of Dijon University Hospital

• Patient participating in another clinical trial

• Patient not affiliated to national health insurance

• Patient unable to complete assessment scales

• Patient under psychiatric care without consent or under legal protection (guardianship, curatorship)

• Major incapable or unable to provide consent