A 1-year pilot study of vagus nerve stimulation in treatment-resistant rapid-cycling bipolar disorder.
OBJECTIVE
Vagus nerve stimulation (VNS) appears to be an effective treatment option for patients with treatment-resistant unipolar and bipolar depression. The aim of the present study was to investigate the efficacy of VNS in a group of patients with treatment-resistant rapid-cycling bipolar disorder (RCBD) who were excluded from previous trials.


METHODS
Nine outpatients with a DSM-IV-TR diagnosis of treatment-resistant RCBD were treated for 40 weeks with open-label VNS. The first patient was enrolled in June 2001, and the last patient completed the study in July 2005. Patients recorded their depression and mania mood symptoms on a daily basis throughout the study using the National Institute of Mental Health prospective life charting methodology and daily mood ratings. Patients were assessed every 2 weeks during the 2-month baseline period before device activation, every 2 weeks for the remaining 40 weeks of the study, and at the end of the study with the 24-item Hamilton Rating Scale for Depression (HAM-D-24), the 10-item Montgomery-Asberg Depression Rating Scale (MADRS), the Young Mania Rating Scale (YMRS), the Clinical Global Impressions (CGI) scale, the Global Assessment of Functioning (GAF) scale, and the 30-item Inventory of Depressive Symptomatology Self-Report (IDS-SR-30). Any adverse events or device complications were also recorded at each visit. The prospective life charts were analyzed by calculating the area under the curve. Statistical analysis was performed with a mixed-model repeated-measures regression analysis for repeated measures of the various rating scales. Significant p values were < or = .05.


RESULTS
Over the 12-month study period, VNS was associated with a 38.1% mean improvement in overall illness as compared to baseline (p = .012), as well as significant reductions in symptoms as measured by the HAM-D-24 (p = .043), MADRS (p = .003), CGI (p = .013), and GAF (p < .001) rating scales. Common adverse events were voice alteration during stimulation and hoarseness.


CONCLUSIONS
These data suggest that VNS may be an efficacious and well-tolerated treatment option for patients with treatment-resistant RCBD. Currently, no comparison is available in the literature. Larger randomized trials are needed to verify these findings.
Marangell
Lauren B
LB
Mood Disorders Center, Menninger Department of Psychiatry, Baylor College of Medicine, and Department of Veterans Affairs, Houston, Texas, USA. drlauren@lilly.com
Suppes
Trisha
T
Zboyan
Holly A
HA
Prashad
Sandhya J
SJ
Fischer
Grace
G
Snow
Diane
D
Sureddi
Suresh
S
Allen
John C
JC
D000328:Adult; D017668:Age of Onset; D018692:Antimanic Agents / Q000627:therapeutic use; D001714:Bipolar Disorder / Q000188:drug therapy / Q000628:therapy*; D004599:Electric Stimulation Therapy / Q000009:adverse effects / Q000379:methods*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011569:Psychiatric Status Rating Scales; D013997:Time Factors; D016896:Treatment Outcome; D014630:Vagus Nerve
D018692:Antimanic Agents