Prefrontal Cortex Stimulation as Treatment for Crack-cocaine Addiction

Forty subjects between 18 and 60 years old, both genders, with a diagnosis of dependence on crack-cocaine, evaluated for the first time at the Center for Psychosocial Care for Alcohol and Other Drugs (CAPS-AD, in Portuguese) in the municipality of Serra, ES, Brazil, will be invited to participate in this study. After triage, following the inclusion and exclusion criteria, they will be informed in details about the experimental protocol and, if they agree to participate, it will be required to sign an Informed Consent. It Will be applied a structured anamnesis, made a psychiatric clinical and physical examination. The treatment will be started with regular medications for abstinence and comorbidities and psychosocial approaches usually done in the CAPS-AD. After selected they will be referred to the Laboratory of Cognitive Science and Neuropsychopharmacology of the Postgraduate Program in Physiological Sciences from Health Sciences Center of Federal University of Espírito Santo where they will be semi-randomly (matched for age, gender and sociodemographic characteristics) distributed into two different groups: (A) sham-tDCS (n = 20) and (B) active-tDCS (n = 20); and they will follow for 10 applications in daily sessions, excepting on weekends, of transcranial direct current stimulation (tDCS, 5 x 7 cm2, 2 mA, 20 min) over the left dorsolateral prefrontal cortex or sham procedure. Event-related potentials (ERP) will be recorded before, during and after brain stimulation or sham procedure under random presentation of three related images and three non-related images to crack use. The compulsive behavior will be evaluated before and after the ERP records. Cognitive tests which assess mental function, frontal function, visuospatial and verbal working memory, inhibition, and conflict resolution will be performed. The depression will be assessed during the treatment, and the addicted subjects will be evaluated once a week for four consecutive weeks after a series of applications of sham-tDCS or active-tDCS.

Inclusion criteria

• fulfill the criteria for the crack-dependence syndrome, based on criteria of the International Classification of Diseases on its 10th version;
• all users and addicts who make use of crack-cocaine alone or in combination with other drugs (alcohol, nicotine, caffeine, cannabis, etc.), or who have psychiatric comorbidities (anxiety, depression, etc.)
• must be clinically stable and not requiring hospitalization;
• should be clinically suitable for the treatment proposed in this study;
• need to be able to read, write and speak Portuguese

Exclusion criteria

• should not present current or past illnesses that may be aggravated during treatment;
• may not show abnormalities in laboratory tests which suggest a deterioration of its physical condition for participation in the study;
• individuals who have some metal in the brain or skull (chips, fragments, pins, etc. - except titanium);
• history of epilepsy, severe brain trauma, cochlear implant, cardiac pacemaker or intracardiac metal apparatus);
• pregnants.