Hamilton rating scale for depression-21 modifications in patients with vagal nerve stimulation for treatment of treatment-resistant depression: series report.

Vagal nerve stimulation (VNS) has been approved for treatment of refractory depression (or treatment-resistant deperssion) and bipolar disorder in Europe and Canada since 2001 and in United States since 2004 by the Food and Drug Administration. Several lines of evidence support an effective antidepressant effect with such treatment modality, outcomes being mainly evaluated with Hamilton Rating Scale for Depression (HRSD). We here report a series of nine patients with severe treatment-resistant deperssion. They all underwent surgical intervention of implantation of left vagal nerve electrode at our institute. The preoperative psychiatric status and postoperative clinical outcome were both evaluated with the 21-item version of the HRSD (HRSD(21) ). Five out of nine patients, having at least one-year follow-up, were responders (≥50% reduction of HRSD scoring) and four of these also were remitters (HRSD < 10). One patient with bipolar II disorder and one patient with melancholic depression did not significantly benefit from the procedure; the latter three patients have follow-ups shorter than three months and one of them meets the remittance criteria; nonetheless, for the other two , HRSD(21) score is gradually decreasing with time.