39 This finding was replicated in a longitudinal follow-up study of long-term outcome of children with tic-related OCD, in which a higher childhood 10 was associated with increased severity of OC symptoms in adulthood.47 Recently, Bloch et al (unpublished

data) reported that a greater verbal-performance IQ discrepancy was associated with pediatric onset OCD. This association of verbal-performance IQ discrepancy and OCD was still significant, after adjusting Inhibitors,research,lifescience,medical for full-scale IQ, age, and gender and excluding OCD subjects with comorbid ADHD or TS. Again, it will be crucial to determine if this is a ”trait“ marker. If it is, then it will be important to determine when this neurophysiological profile first becomes evident, and whether or not it is associated with specific OC symptom dimensions or subtypes of disease. A final promising Inhibitors,research,lifescience,medical endophenotype concerns potential ABT 869 deficits in sensorimotor gating and the use of electroencephalographic (EEG) and magnetoencephalographic (MEG) recordings to identify at-risk individuals. As in TS and schizophrenia, some individuals with OCD present, with deficits in sensorimotor gating typically defined through a reduction in prepulse inhibition.125,126 These deficits may help us understand how normally occurring intrusive thoughts

(eg, a thought about harm coming to one’s own child) come to be regarded as highly meaningful (eg, “This thought means I am a terrible Inhibitors,research,lifescience,medical person and a potential danger to my child”); and how once they are established they can create

a vicious cycle that to some degree is self rinforcing. We speculate that neurons within the frontal-striatal-thalamo-cortical circuits Inhibitors,research,lifescience,medical form behavior-dependent oscillating networks of various sizes and frequencies that bias input selection in favor of these normally occurring thoughts and their negative appraisal, and that at least in some cases this Inhibitors,research,lifescience,medical is due to a loss of striatal interneurons.127-129 Coherent activity within these networks is likely to modulate sensorimotor gating as well as to lead to goal-directed motor actions. When these networks are dysrhythmic, there may be a loss of control of sensory and cognitive inputs and subsequent motor action. The no known electrophysiological effects of medications, repetitive transcranial magnetic stimulation, and surgical interventions used to treat OCD are likely to have an ameliorative effect on these aberrant oscillations.130,131 Similarly, a case can be made that successful behavioral treatments involve the willful training of regions of the prefrontal cortex not to make a motor response to these unwanted cognitive and sensory urges, so that these prefrontal regions can become effective modulators of aberrant thalamocortical rhythms. Conclusions In addition to the existence of subtypes of OCD, a strong case can be made to support the use of a dimensional approach to OC symptoms.