Deep Brain Stimulation to Understand and Treat Addiction

Change in Number of Drinking Days per Week (Timeline Followback)

Alcohol use will be assessed using the Timeline Followback (TLFB), a validated self-report measure of daily alcohol consumption. Participants will report the number of days per week on which alcohol was consumed. TLFB data are collected for a 6-month pre-surgical baseline, monthly during the 6-month open-label optimization phase, and monthly during the 4-month randomized cross-over phase. Changes in drinking frequency across phases and stimulation conditions will be compared to evaluate the effect of deep brain stimulation on alcohol use.

Change in Number of Alcohol Units Consumed per Week (Timeline Followback)

Weekly alcohol intake will be quantified using the Timeline Followback (TLFB). The total number of standard UK alcohol units consumed per week will be calculated from participant self-report. TLFB data are collected for a 6-month pre-surgical baseline, monthly during the 6-month open-label optimization phase, and monthly during the 4-month randomized cross-over phase. Changes in total weekly consumption across phases and stimulation conditions will be compared to determine the effect of deep brain stimulation on overall drinking volume.

Adverse Events Related to Surgery or Stimulation

All adverse events related to DBS surgery, the implanted device, or stimulation are recorded and reviewed by the clinical and research teams. Events are categorized by severity (mild, moderate, severe) and relatedness (unrelated, possibly related, related). Higher severity classifications indicate more serious adverse outcomes.

Change in Alcohol Craving (Alcohol Urge Questionnaire)

Alcohol craving will be assessed using the Alcohol Urge Questionnaire (AUQ), a validated self-report measure of desire to drink, anticipated effects, and perceived control over drinking. Scores range from 8 to 56, with higher scores indicating stronger craving. Participants complete the AUQ daily during the open-label and randomized phases and monthly during laboratory sessions.

Quality of Life (Short Form Health Survey)

Health-related quality of life will be assessed with the Short Form Health Survey (SF-36), a 36-item self-report measure comprising eight domains of physical and mental health. Domain scores are transformed to a 0-100 scale, with higher scores indicating better health status. Physical and Mental Component Summary scores may also be calculated, with higher scores reflecting better quality of life.

Illness Severity (Clinical Global Impression)

Illness severity and clinical change over time will be assessed with The Clinical Global Impression (CGI) scale. The CGI-Severity (CGI-S) is a clinician-rated measure of current illness severity ranked on a 7-point scale, whereby the CGI-Improvement (CGI-I) rates change from baseline on a 7-point scale. Lower scores indicate lower severity and greater improvement.

Momentary Mood, Craving, Anxiety (0-100 VAS via WebApp)

Participants complete high-frequency ecological momentary assessments (EMAs) via a smartphone-based web application up to five times per day. Each EMA consists of composite of single-item visual analogue scale (VAS) questions assessing current depression, anxiety, and craving (e.g., "What is your craving right now?"). Responses are recorded on a continuous scale from 0 to 100, where 0 indicates none/not at all and 100 indicates the most extreme level. Higher scores indicate greater levels of the assessed state.