Radiosurgical Neuromodulation for Refractory Depression

Main objective: To determine the safety of Radiosurgical Neuromodulation (RSN) for Refractory Depression using X-rays in a population of subjects with severe treatment resistant bipolar depression over a 12-month observational period post treatment. While almost any radiosurgical device could be used, the research team has extensive experience with the Accuray CyberKnife System, K011024, and it will be used for planning and delivery of the 6 megavolt (MV) X-ray treatment for this study. Participation will be dependent upon subjects having a diagnosis of bipolar depression and meeting criteria for treatment resistance. Treatment resistance will be defined as a failure to show clinical improvement after at least four different medication trials and/or one course of electroconvulsive therapy (ECT) during the current episode. A medication trial is defined as an adequate dose and duration of one of four classes of psychoactive medications: lithium, anticonvulsant mood stabilizers, atypical antipsychotic mood stabilizers, and/or antidepressant medications. One course of ECT is defined as receiving six acute treatments. The study will include subjects who have failed ECT, or have had intolerable side effects to ECT, or elected not to receive such treatment due to stigma, or concern over possible side effects of the ECT treatment itself. The subjects enrolled will have exhausted all reasonable treatment strategies, and currently have no other reasonable or viable treatment options for their illness. Secondary objective: To examine clinical outcome initially over 3 months, then with follow up at 6, 9 and 12 months. Depression will be assessed using the Hamilton Depression Rating Scale (HDRS) 24 item, while manic symptoms will be measured by using the Young Mania Rating Scale (YMRS), and the Clinical Global Impression of Severity of illness (CGI-S), and Improvement (CGI-I). A battery of neuropsychological tests will be administered as well, assessing memory with the California Verbal Learning Task (CVLT), prefrontal function using a Delas-Kaplan Executive Function System (DKEFS) battery including the DKEFS Sorting task, DKEFS Trails task, DKEFS color-word interference task, and the DKEFS verbal fluency task. In addition, the investigators will request information regarding any possible adverse events that occur during this trial. The intended use for the CyberKnife System, the radiosurgical device being used in this research study, is to administer radiomodulation to the cingulate cortex target Cg25 in patients with refractory bipolar depression.