Although obsessive-compulsive disorder (OCD) was once considered rare, recent epidemiologic data suggest a lifetime prevalence rate of 2% to 3%. The morbidity associated with OCD is quite high compared to other psychiatric conditions. This report reviews neurologic, neuropsychological, and psychosurgical findings relevant to the functional neuroanatomy of OCD. In addition, it describes more recent investigations of OCD using a variety of brain imaging techniques, including computed tomography, positron emission tomography, and single photon emission computed tomography (SPECT). Finally, it examines the results of an ongoing pilot study of high-resolution, full-volume, three-dimensional SPECT imaging in patients with OCD before and after treatment with fluvoxamine.
"Although the molecular causes of OCD remain unsolved, a dysfunction in a neuronal loop running from the orbital frontal cortex to the cingulate gyrus, striatum (caudate nucleus and putamen), globus pallidus, thalamus, and back to the frontal cortex has been suggested. This hypothesis is supported by neurological (Laplane et al, 1989), neurosurgical (Mindus et al, 1994; Oliver et al, 2003; Rauch, 2003), and imaging findings (Baxter et al, 1992; Breiter et al, 1996; Saxena et al, 1998; Trivedi, 1996). The exact nature of the molecular events that evoke OCD symptoms is not known and several hypotheses have been put forward. "
[Show abstract][Hide abstract] ABSTRACT: Changes in D(2) receptors during antidepressant therapy have been reported in patients with major depressive disorder using PET/SPET. The aim of this study was to evaluate modifications in D(2) receptors that might occur in patients affected by obsessive-compulsive disorder (OCD) during serotonin reuptake sites inhibitors (SSRIs). To this purpose, we measured the in vivo binding of [(11)C]raclopride ([(11)C]Rac)in the brain of a group of OCD naïve patients before and after the repeated administration of the inhibitor SSRI fluvoxamine. Eight patients with a Diagnostic and Statistical Manual of Mental Disorders IVth edition diagnosis of OCD completed the study undergoing a PET scan and a complete clinical evaluation before and during treatment with fluvoxamine. Patients have been compared also with a group of nine age-matched normal volunteers. Fluvoxamine treatment significantly improved clinical symptoms and increased [(11)C]Rac binding potential (BP) in the basal ganglia of OCD patients (7.5+/-5.2, 6.9+/-6.9, and 9.9+/-9.3% in dorsal caudate, dorsal putamen, and ventral basal ganglia, respectively; p<0.01) to values closer to those observed in the group of normal subjects. Chronic treatment with fluvoxamine induces a slight but significant increase in striatal [(11)C]Rac BP of previously drug-naïve OCD patients. The modifications in D(2) receptor availability might be secondary to fluvoxamine effects on serotoninergic activity.
"Although OCD was previously considered to be refractory to most types of therapeutic intervention, there is now ample evidence that both pharmacological intervention, namely serotonin re-uptake inhibitors (SRIs) (Greist et al., 1995; Goodman, 1999), and specific behavior therapies that employ the principles of exposure and response prevention (EyRP), are highly effective in reducing the symptoms of OCD (Rachman et al., 1971; O'Sullivan et al., 1991). Functional neuroimaging techniques yield images that reflect indices of brain activity, and these could provide much valuable information regarding the mediation of OC symptoms (Insel, 1992; Trivedi, 1996; Rauch and Baxter, 1998). "
[Show abstract][Hide abstract] ABSTRACT: Very few functional neuroimaging studies have been performed on patients with obsessive-compulsive disorder (OCD) undergoing behavior therapy, even though it is recognized to be an effective treatment for this disorder. We measured the regional cerebral blood flow (rCBF) using the Xenon inhalation method in 31 treatment-refractory patients with OCD and the same number of age-matched normal controls. We also studied changes in rCBF in 22 OCD patients who had demonstrated a significant improvement after the behavior therapy. The OCD patients showed a significant bilateral elevation in the rCBF in the basal ganglia compared with the normal controls. After successful treatment, a significant decrease was found in the rCBF in the right head of the caudate nucleus that tended to correlate with clinical improvement.
Psychiatry Research 11/2003; 124(2):113-20. DOI:10.1016/S0925-4927(03)00069-6 · 2.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Obsessive-compulsive disorder (OCD) has been studied extensively in recent years, with increased emphasis on understanding
OCD’s biological substrates. There has been significant progress in documenting abnormal brain function in OCD patients, particularly
in the orbitofrontal cortex, basal ganglia, and thalamus. Similar progress has broadened our understanding of the cognitive
and behavioral manifestations of the disorder, including deficits in set shifting, hyperattention, and visuospatial construction
abilities. Unfortunately, these results have not been replicated consistently. This report comprises a review of previous
attempts to characterize the neurobiology and neuropsychology of OCD, and a discussion of several factors in OCD research
that can help to explain previous inconsistencies.
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