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jabbrv-ltwa-en.ldfDiscussion
In this case report, we describe the short- and long-term treatment
responses from DBS in the BNST and MFB areas in two patients with
treatment-resistant depression and severe and disabling anxiety
manifested as GAD. Both patients achieved remission from depression
following short-term DBS in the BNST, and one of the patients had a
major reduction in anxiety symptoms. However, DBS in the MFB area showed
no clear short-term effects on depressive or anxiety symptoms. During
the open-label phase, both patients continued to receive BNST-DBS. One
of the patients had several trials of DBS in the MFB area but did not
experience any additive effect on depression, in addition to the
anxiolytic effect of DBS in BNST. After four to five years, stable
reductions in depressive and anxiety symptoms were recorded in both
patients and the level of global functioning had increased.
In line with our findings, reduced anxiety or depressive symptoms have
been previously reported in DBS studies on treatment-resistant
depression (16,18,23), in OCD (12,13,24,25), and in two case reports on
patients with comorbid anorexia nervosa, depression, and GAD (7,8). In
the studies mentioned above, brain targets in the anxiety regulation
network were stimulated (9). Thus, we speculate that DBS in areas
believed to affect the anxiety regulation network might be more
effective in treatment-resistant depression with a clear anxiety
component.
The absence of a short-term antidepressant effect from DBS in the MFB
area in the two cases could be due to several factors, such as a
suboptimal placement of the electrodes, or a too-short stimulation
period to achieve a sufficient antidepressant effect as previously
discussed (26). In this report, the target area of the MFB was
identified on a T2 MRI, based on the visualization of the subthalamic
nucleus, red nucleus, and corpora mammillaria. However, it has been
suggested that tractography (27,28) or intracranial electrophysiology
recordings (29) are more precise methods to determine the electrode
position.