Distinctive somatosensory evoked potential features in obsessive-compulsive disorder.

The purpose was to determine whether obsessive-compulsive disorder (OC) is associated with a distinctive pattern of somatosensory evoked potential (SEP) measurements, based on amplitudes of the N60 (negativity 60 msec poststimulus), P90, and N130 peaks. Previously, we found higher N60 amplitudes in 14 OC patients than in controls or other neurotics. Here, SEPs of the same 14 OCs were compared with those of 28 other neurotics, 99 nonpatients, 49 chronic schizophrenics, 27 "other" schizophrenics, 20 DSM-II latent schizophrenics, and 42 major depressives. Utilizing all available subjects, each peak amplitude was factor analyzed across 14 leads; the resulting factor scores were compared between OCs and every other group. The factor scores of OCs differed from those of all other groups, and patterns of factor score differences were similar in all comparisons. Most discriminations were replicable in split-half analyses. OC appears to be associated with a relatively distinctive pattern of middle latency SEP peak amplitude measurements.