Bilateral Prefrontal Modulation in Crack-cocaine Addiction

Phase 2

Completed

Brief Summary: In this study, eligible crack-cocaine addicted inpatients recruited from specialized clinics for substance abuse disorder treatment, filling inclusion criteria and not showing any exclusion criteria, were randomized to receive the repetitive (10 sessions, every other day) bilateral dorsolateral Prefrontal Cortex (dlPFC: cathodal left / anodal right) tDCS (2 milliamperes, 3x7 cm2, for 20 min) or placebo (sham-tDCS). Craving to the use of crack-cocaine was examined before (baseline), during and after the end of the tDCS treatment.

Based in our previous data, our hypothesis was that repetitive bilateral tDCS over dlPFC would favorably change clinical, cognitive and brain function in crack-cocaine addiction and these would be long-lasting effects.

Detailed Description: Before (baseline) and after tDCS or sham-tDCS treatment, subjects were examined:

(1) clinically, regarding craving (obsessive compulsive scale) and relapses to the drug use.

They were followed-up for clinical examination at least 60 days after treatment.

Recruitment & Eligibility

Inclusion Criteria

patients between the age of 18 and 60 years;
met criteria for crack-cocaine dependence according to the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5), as determined by clinical evaluation;
in stable clinical condition with no need for inpatient care;
able to read, write, and speak Portuguese; and
no severe withdrawal signs or symptoms at baseline.

Exclusion Criteria

a condition of intoxication or withdrawal due to a substance other than crack-cocaine;
unstable mental or medical disorder or substance abuse or addiction other than crack-cocaine dependence, except nicotine and/or caffeine;
a diagnosis of epilepsy, convulsions;
a previous history of drug hypersensitivity or adverse reactions to diazepam or other benzodiazepines and haloperidol;
any contraindication for electrical brain stimulation procedures such as electronic implants or metal implants;
suspected pregnancy for female participants;

Arm && Interventions

Group	Intervention	Description
real tDCS	transcranial Direct Current Stimulation	Ten sessions (every other day) of bilateral transcranial Direct Current Stimulation (tDCS: 2 milliamperes, 3 x 7 cm2, during 20 minutes) over dorsolateral Prefrontal Cortex (cathodal left / anodal right).
sham-tDCS	transcranial Direct Current Stimulation	Ten sessions (every other day) of placebo control (sham procedure) of transcranial Direct Current Stimulation (sham-tDCS) during 20 minutes with electrodes placed over the dorsolateral Prefrontal Cortex (cathodal left / anodal right). Current was delivered for 30 seconds and was turned off for the rest of the stimulation period. In this way, subjects experienced the initial itching sensation at the beginning of stimulation, but received no current for the rest of the session.

Primary Outcome Measures

Name	Time	Method
Craving	Five applications: once in the week before tDCS treatment (baseline), second, third and fourth weeks, during the treatment, and in the fith week, after the end of the tDCS treatment.	Five items from the original obsessive compulsive drinking scale, which are believed to reliably assess craving in a narrow sense were used. Questions of this brief scale allow quantification of thoughts and feelings (obsessions), and behavioral intentions, and are answered on a scale ranging from 0 to 4, resulting in a total score between 0 and 20. Higher scores reflect more severe craving. These items were applied at the beginning, during and at the end of the treatment with sham-tDCS or tDCS.
Relapses	30 and 60 days after discharge from clinics	A use relapse was defined as the first episode of return to the previous uncontrolled pattern of crack-cocaine use (rocks per day). Information about relapse were gathered directly when patients regularly returned to the hospital for clinical follow-up after their discharge and/or by self-report or reports of family members by telephone calls.

Secondary Outcome Measures