Two-point discrimination thresholds and schizotypy: illuminating a somatosensory dysfunction.

The current study sought to determine if somatosensory deviations, assessed by determining two-point discrimination thresholds, were associated with schizotypic features in non-psychotic subjects (N=100). It was hypothesized that elevated two-point discrimination thresholds would be associated with an increased likelihood of higher levels of schizotypy features. The results of the study suggested that at the level of individual differences, higher two-point discrimination thresholds (ascending series assessments) were associated with higher levels of schizotypy as operationalized by several prominent measures of schizotypy. A deviant subgroup analysis clearly suggested that, for ascending series two-point threshold assessments, those persons requiring the greatest distance (i.e. highest thresholds) to detect two-point stimulation were substantially more schizotypic than a contrast group. Control analyses that focused on psychological state (depression, anxiety) and intellectual functioning variables revealed that these factors were, more or less, unrelated to two-point discrimination thresholds and they did not account for the observed significant relations between the schizotypy scales and two-point threshold values. The results of this study are discussed within a neuropsychological context implicating parietal cortex involvement with schizotypy and schizophrenia.