Repetitive Transcranial Magnetic Stimulation (rTMS) of the Insula for Treatment of Alcohol Addiction

Objectives: To investigate the effects of repetitive transcranial magnetic stimulation (rTMS) targeting the insula on alcohol use and neural responses in alcohol-dependent patients. Study population: Treatment seeking alcohol dependent subjects (N=82), aged 18-65 years, who have first completed standard alcohol withdrawal treatment if needed. Design: This is a double-blind, sham-controlled randomized study, comprising three phases. Participants will be hospitalized during the first two of these, and will be outpatients during the third. During Phase 1 the study (screening; up to 14 days), participants will undergo a set of baseline assessments; this phase will conclude with consent, inclusion and randomization. During Phase 2 (treatment; appr. 3 weeks, with at least the first week being hospitalized), participants will first undergo an MRI scan to collect resting state and structural data, and will then receive one of two treatments: Active (10Hz) rTMS; or sham stimulation, both targeting the insula bilaterally. rTMS sessions will be conducted five times per week, for 3 weeks, for a total of 15 sessions. Stimulation will be with an H-coil designed to reach deeper structures such as the insula. A second MRI scan will be obtained at the end of this phase to assess changes in resting state connectivity, and to evaluate insula activity in tasks known to activate this structure. In addition, a lumbar puncture will be carried out at the end of this phase to assess possible effects on central neurotransmitter and growth factor levels, as indexed in the cerebrospinal fluid. For Phase 3 (follow-up, lasting 12 weeks), patients will be followed as outpatients for 12 weeks, with clinic visits at weeks 1, 2, 4, 8 and 12 post discharge; measures of alcohol use will be collected during this phase. Outcome measures: The co-primary outcome measures will be heavy alcohol consumption during the follow-up phase, assessed using time-line follow-back methodology; and insula BOLD functional magnetic resonance imaging (fMRI) responses during tasks known to induce insula activation. A number of secondary and exploratory measures will also be assessed, including objective biomarkers of alcohol consumption.