A Controlled Trial of Transcranial Direct Current Stimulation as a Treatment for Unipolar and Bipolar Depression.
Study Design - The initial study phase uses a randomized, triple-blind, 2-group parallel, sham-controlled design. Patients will be asked to attend 20 tDCS sessions conducted on consecutive weekdays over a 4-week period. Patients will be randomly assigned by computer to one of 2 groups: bifrontal (BF) active tDCS or sham tDCS. Randomization will be stratified based on unipolar or bipolar depression. after the initial blinded, sham-controlled phase, participants who do not meet the criterion for remission (MaDRS score [Less Than] 10) will be offered further treatment in an open label phase consisting of 20 active tDCS sessions also conducted on consecutive weekdays over 4 weeks. Patients who have completed 4 or [Greater Than] weeks of daily tDCS will enter a Taper phase after receiving daily treatments. The Taper phase will consist of 4 further tDCS treatments, a week apart, leading up to the 1 month follow up. Patients will not be unblinded to their tDCS condition until after the entire study is completed. Mood and neuropsychological function will be assessed at set intervals.
tDCS Procedures - Treatment sessions in the trial will be on consecutive weekdays. active stimulation parameters will be 30 minutes per session at 2.5 ma with 30 seconds ramp up and 30 seconds ramp down. The anode will be placed on the left dorsolateral prefrontal cortex at F3 (10/20 eeG system) and the cathode over the lateral right frontal area at F8. For sham stimulation, the current will be switched on for 30 seconds at 1 ma with 10 seconds ramp up and 10 seconds ramp down. at the end of each tDCS session, skin redness at electrode sites will be checked and participants will be asked about the presence of the following side effects: itchiness, tingling, burning, pain, dizziness, lightheadedness, headache, blurred vision, fatigue and nausea. The active tDCS stimulation parameters was determined based on previous tDCS trials, which demonstrated greater antidepressant efficacy with higher current intensity. These studies have also involved more frequent tDCS sessions and a greater number of sessions. Based on previous tDCS studies this current study is attempting to further evaluate and potentially optimize the stimulation parameters of tDCS. The tDCS stimulation parameters for this study are also within proposed safety limits of tDCS. These safety limits are based on theoretical calculations and empirical testing in animal models, including a recent study investigating a wide range of combinations of current intensity and stimulation duration (agnew and McCreery, 1987; Liebetanz et al., 2009; nitsche et al., 2003; Priori, 2003).
assessments - Clinical efficacy will be assessed by changes from baseline in a variety of clinician rated and self-reported measures. Mood will be assessed prior to the first tDCS session and at specified visits during the sham-controlled and open label phases. Primary outcome measure: MaDRS. Response is defined as [GreaterThanorequalTo]50% decrease in MaDRS score from baseline to trial completion. Remission or recovery is defined as a MaDRS score of less than 10. Secondary outcome measures: CGi x Severity of illness and Clinician Global impression x improvement and the self-rated version of the Quick inventory of Depressive Symptomatology. The Young Mania Rating Scale and altman Self Rating Mania Scale will be used to check for mood elevation.
Various neuropsychological tests will also be administered:
Montreal Cognitive assessment
California Verbal Learning Test-ii
Ruff 2 and 7
WaiS-iV Digit Span
Symbol Digit Modality Test
D-KeFS Verbal Fluency
Cognitive Failures Questionnaire
Quality of Life enjoyment and Satisfaction Questionnaire x Short Form
at each session, patients will be asked [Quote]How have you been since the last visit?[Quote]. Comments will be documented on the Treatment Sheets. after each tDCS session, participants will be asked about side effects using a structured questionnaire.
1. 18 years of age or above.
2. Meets criteria for a DSM-IV Major Depressive Episode with duration of at least 4 weeks.
3. Total score greater than or equal to 20 on the Montgomery-Asberg Depression Rating Scale at study entry.