tDCS in Treatment of Craving in Sexual Addiction (CAS)

Transcranial Electrical Stimulation in Sexual Addiction: an Innovative Treatment for a Better Understanding of the Physiopathology of Craving

In patients with addiction to a substance, an increase in activity in the prefrontal cortex induced by transcranial Direct Current Stimulation -tDCS (non-invasive technique, modulating cortical activity by applying low-intensity electrical currents between two electrodes),may help reduce craving in people addicted to alcohol and tobacco. By analogy with addictive behavior with a substance, the craving observed in certain behavioral addictions would involve the same neural circuits. The main hypothesis is to reduce the sexual craving associated with the viewing of erotic images during active brain stimulation compared to placebo stimulation. Functional MRI will allow to better understand the neural circuits involved in sexual addiction and in the expected inhibition of sexual arousal by tDCS in sexual addictions during visualization erotic images.

The concept of sexual addiction appeared in American literature about 20 years ago. The term sexual addiction describes an excessive, increasing, and especially uncontrolled frequency of sexual behavior, as a conventional rule, associated with a compelling and irrepressible sexual desire (craving), which persists in spite of the possible negative consequences and personal suffering of the subject. The prevalence of this condition is estimated to be approximately 3-6% in the general population in the United States, it is independent of the socio-cultural environment. The pathophysiology of sexual addictions remains very poorly understood. Numerous studies have focused on substance addictions and their pathophysiology. The mesolimbic dopaminergic system plays a major role in addictive behavior. The prefrontal cortex and the basolateral region of the amygdala play an important role in the craving and may cause relapse in subjects. In subjects with sexual addiction, only one controlled study has been conducted on the role of antidepressant treatment in the reduction of craving. The objective of the study is not only to evaluate the efficacy of tDCS neurostimulation in this disorder but also to identify the brain structures involved in this addictive disorder.

Quantitative data regarding the intensity of emotional response and craving to erotic images, motor inhibition task and impulsivity will be presented in the form of frequency, mean and standard deviation (SD) calculations and compared using a 2-factor repeated measures ANOVA taking into account the fact that the patient will be compared to himself (position 1 and 2 and placebo) and to other patients using 3 kinds of images (erotic, social and neutral) with 3 types of possible stimulations. In order to analyze the fMRI data, the regions of the patient's body will be identified. in which the BOLD activity will be correlated to the attractiveness of the image. Foreach patient, the difference before and after stimulation will be calculated. There will be no intermediate analysis.

Depending on the randomized group, the subject will receive one of two treatments 15 days apart (A: active anode on the right DLPFC and neutral cathode on the left shoulder; B: inactive anode on the DLPFC and inactive cathode on the left shoulder). The groups are defined as follows: The results of randomization will not be known by the evaluator.

25 patients with sexual addiction will be stimulated by sham tDCS stimulation (placebo) during 5 consecutive days

5 active sessions (1/day for 5 consecutive days) of tDCS (NeuroConn DC), active anode 8cm2 on right dorso-lateral prefrontal cortex and neutral cathode, 2 mA, during 30 min will be performed

5 placebo sessions (1/day for 5 consecutive days) of sham tDCS (NeuroConn DC), anode 8cm2 on right dorso-lateral prefrontal cortex and neutral cathode during 30min will be performed

The primary outcome is to assess the effectiveness of tDCS treatment on the reduction of the craving by comparing before and after active tDCS stimulation in response to erotic-pornographic images. Efficacy will be quantified by a sexual craving scale associated with erotico-pornographic images before and after tDCS stimulation. A significant decrease in craving and score on the scale is expected after tDCS stimulation. compared to control subjects. Images of social and neutral interactions will be used as comparison of expected changes. The scale used is the PATHOS scale: brief sexual addiction screening questionnaire.

For the evaluation of efficacy of tDCS in emotional response, indirect measurement of craving, visual emotional responses scales (Likert) will be used during visualization of erotico-pornographic images, before and after stimulation. The "desire" will be quantified on a Likert scale from 0 to 7.

An assessment of emotional responses will also be done using heart rate measure during visualization of images in fMRI, before and after stimulation by tDCS

The secondary objectives are the evaluation of the brain structures involved in sexual addiction, especially craving, and the study of the modifications of the circuits involved after the application of tDCS. A modification of the BOLD signal in fMRI in the mesolimbic reward system as well as in the dorsolateral prefrontal cortex, orbitofrontal cortex and the amygdala in response to erotic images is expected after tDCS. 50 patients with sexual addiction will be compared with 25 healthy subjects for this objective

In addition, the evaluation of impulsivity and inhibition capacities of the frontal cortex will be conducted.Changes in impulsivity scale scores and motor inhibition task scores are expected after tDCS.

A decrease in scores on this scale is expected after stimulation compared to patients who received placebo stimulation.

A decrease in scores on this scale is expected after stimulation, compared to patients who received placebo stimulation.

Inclusion Criteria: 18-60 year old male Heterosexual Right-handed (Manual laterality test) With a sexual addiction (PEACCE Tool> 3 and Carnes ≥ 13/25) except for controls Having signed a written and informed consent Subject benefiting from social security Exclusion Criteria: Subject presenting a medical pathology requiring drug treatment, Severe psychiatric pathology (bipolar disorder, hyperactivity or schizophrenia) or another addiction (alcohol, illicit substances or behavioral addiction) Subject consuming psychotropic drugs in progress or during the last month Subject not understanding French Subject under tutorship or curatorship Subjects with neurological disease including epilepsy or a history of head trauma Subjects hospitalized in enforced hospitalization Subject presenting a contraindication to tDCS: subject with an electrical or metal brain implant Subject with a contraindication to MRI

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