Although significant progress has been made over the last decade in the treatment of obsessive-compulsive disorder (OCD), approximately 20% of OCD patients remain refractory to nonsurgical therapies, including pharmacologic and cognitive-behavioral therapy. Because a number of neural circuits involving the basal ganglia, thalamus, limbic system, and frontal lobes have been implicated in the pathophysiology of OCD, the need for an effective intervention in these patients has brought the focus on surgical approaches, including cingulotomy and capsulotomy procedures. Unlike free-hand surgical approaches used in the past, current neurosurgical interventions have been greatly enhanced by advances in technology, which allow lesioning to an accuracy of 1 mm. Today's neurosurgical approaches have shown significant benefit in as many as 60% of refractory patients, while preserving personality and cognitive functioning and limiting morbidity. A study of gamma knife capsulotomy conducted at Brown University School of Medicine showed that 40% of patients undergoing two lesioning procedures were much or very much improved 2 years postsurgery. The inherent obstacles to conducting placebo-controlled studies in these severely ill patients mean that further study is required to identify optimal candidates for surgical intervention.

Despite advances in therapies, there remain psychiatric patients who are extremely ill and cannot be helped by classic psychiatric treatments, including psychotherapy and drug therapy. Certain of these patients may be helped by use of bilateral brain lesioning. The complication rate of standard stereotactic psychosurgery techniques is very low. The main rationale for the continued experimental use of deep brain stimulation (DBS) in neurosurgery for mental disorders is its reversibility. This reversibility is not an advantage in terms of the benefits obtained, but rather if side effects emerge. In addition, electrical stimulation may provide patients with some autonomy for their treatment. The first, very preliminary results of electrical stimulation for obsessive-compulsive disorder and for a small heterogeneous group of patients with other psychiatric disorders have been published. Electrical stimulation of the brain for psychiatric disorders may become a new treatment option for certain intractable psychiatric disorders. Nevertheless, the mechanism of action of DBS in psychiatric disorders is unknown, and the experience with this modality is extremely limited. The first results look promising, but this treatment option may prove unusable for some time because of a lack of knowledge of appropriate brain stimulation targets and technical problems such as the availability of sufficient current supply.

Although the vagus nerve has traditionally been considered to perform efferent functions, in reality it performs significant afferent functions as well, carrying information from the body, head, and neck to the brain. Preliminary studies examining this afferent activity led to the theory that vagus nerve stimulation (VNS) could successfully control seizure activity in persons who are refractory to antiepileptic medications. Unlike other forms of brain stimulation, VNS is unable to directly stimulate multiple discrete areas of the brain; however, through several pathways, it is able to relay sensory information to higher brain regions. An implantable VNS device known as the VNS™ NeuroCybernetic Prosthesis (NCP) System has been used in approximately 9,000 epilepsy patients in Europe and the United States since 1994. The implant has reduced seizure frequency by an average of 25% to 30%, with minimal side effects. Studies underway are also showing some degree of success in the management of treatment-refractory depression. The future efficacy of the implantable system in other disorders may depend on whether the implant can be more precisely focused to affect different brain regions. Research in this area is underway.

The author presents two cases of nonparaphilic sexual addiction (NPSA) with comorbid depression and other psychiatric disorders in which symptoms were relieved during treatment with selective serotonin reuptake inhibitors. NPSA is defined and comorbid disorders, the neurotransmitter hypothesis of sexual function, treatment considerations, and evidence for an obsessive-compulsive disorder vs mood/affect dysregulation disorder etiology for these sexual symptoms are discussed.