Objective and importance: The present report explored the effect of electrical stimulation on the inferior thalamic peduncle in a patient with resistant major depression disorder (MDD).
Clinical presentation: This report refers to a 49-year-old woman with a history of recurrent episodes of major depression for 20 years (12 episodes and 2 hospitalizations), fulfilling Diagnostic and Statistical Manual of Mental Disorders, 4th edition, revised, criteria for MDD; in addition, the patient met criteria for borderline personality disorder and bulimia. Her longest episode of depression with suicidal ideation began 5 years before surgery. The patient's symptom array responded poorly to different combinations of antidepressants, cognitive therapy, and electroconvulsive therapy, which induced improvement only for short periods of time. Immediately before surgery, her Global Assessment of Functioning score was 20 and her Hamilton Depression Scale score ranged from 33 to 42. The patient was proposed for surgery for MDD.
Intervention: The patient had bilateral eight-contact electrodes stereotactically implanted for stimulation of areas at and around the inferior thalamic peduncle. Electrode position was corroborated by unilateral electrical stimulation searching for recruiting responses and regional direct current shifts in the electroencephalogram. Recording electrodes were replaced by tetrapolar electrodes for deep brain stimulation and connected to an internalized stimulation system for continuous bipolar stimulation at 130 Hz, 0.45 milliseconds, 2.5 V. Bimonthly follow-up included psychiatric and neuropsychological evaluations performed over the course of 24 months. After 8 months of ON stimulation, the patient entered a double-blind protocol with stimulators turned OFF. Improvement of depression measured by the Hamilton Depression Scale score was evident after initial placement of electrodes without electrical stimulation. Depression relapsed partially at the end of the first week. Electrical stimulation further improved depression, normalizing depression scores and neuropsychological performance. Patient depression scores ranked between 2 and 8 during 8 months of ON stimulation without antidepressant medication. After stimulation was turned OFF, spontaneous fluctuations in patient symptoms reflected by Hamilton Depression Scale and Global Assessment of Functioning scores were documented; these fluctuations disappeared after stimulation was turned on by Month 20.
Conclusion: Complicated patients with comorbid conditions are common referrals to psychosurgery services. In this report, we present promising results of electrical stimulation of the inferior thalamic peduncle to treat recurrent unipolar depression in a patient with MDD and borderline personality disorder who responded poorly to treatment.