Vagus nerve stimulation. In theory, direct stimulation of the vagus afferent fibers could affect sensory input to limbic, brain stem and cortical areas known to be involved in mood and anxiety disorders. There are currently seven patients with OCD, two patients with posttraumatic stress disorder and one with panic disorder implanted with the device. Acute and long-term data are not yet available on these patients.
Repetitive transcranial magnetic stimulation. Greenberg et al. (1997) treated 12 patients with OCD and found that a single session of right prefrontal repetitive transcranial magnetic stimulation (rTMS) decreased compulsive urges for eight hours, although there was no effect on obsessions. Alonso and colleagues (2001) randomly assigned 18 patients with OCD to real or sham rTMS and did not find any difference between the treatment groups.
Neurosurgery. For treatment-refractory patients with extreme physical and psychological distress including suicidality and significant disability, psychosurgery may be a treatment option. Different procedures including cingulotomy, subcaudate tractotomy, capsulotomy and limbic leucotomy have been employed, with reported response rates of 35% to 65% (Cosgrove, 2000).
It is hypothesized that such lesions disrupt dysfunctional neural circuits by severing connections between the orbitomedial frontal lobes and limbic or thalamic structures. However, the observation that most patients take weeks or months to improve suggests that secondary effects such as nerve degeneration may be important. No conclusive data exist on comparative efficacy or safety of each approach, and there have been no controlled comparisons with sham surgery. The potential long-term side effects, including lethargy and personality changes, should be weighed against the risks of nonintervention.
Conclusion
Effective management of treatment-resistant OCD should employ a stepwise treatment strategy (Figure). Treatment-resistant cases may benefit from consultation with specialized centers where expertise is available for diagnostic reevaluation, as well as intensive CBT and pharmacotherapy. Identifying and tracking the treatment of refractory cases should be an important focus of future research. It is important for a clinician to be persistent, inventive and thorough in the treatment of patients with this prevalent and disabling condition.
Dr. Feusner is a research fellow at the University of California, Los Angeles, Neuropsychiatric Institute. He has experience treating patients in the UCLA OCD Intensive Treatment Program and the Anxiety Disorders Clinic.
Dr. Bystritsky is professor of psychiatry and behavioral sciences at UCLA and director of the Anxiety Disorders Treatment Program and the OCD Treatment-Resistant Program.
