The Development of the Five-Factor Schizoid Inventory.

The current study sought to provide evidence for a measure of schizoid personality disorder (SZD PD) traits using the Five-Factor Model framework of personality. In the first study, undergraduate participants ( n = 496) completed the Five-Factor Schizoid Inventory (FFZI) and other self-report measures. The first half of the sample was used to develop the FFZI, while the second half was used to validate it. The FFZI demonstrated excellent internal consistency, convergent validity with measures of SZD PD and hypothesized IPIP-NEO facets, and discriminant validity with other PDs and non-hypothesized IPIP-NEO facets. The second study recruited MTurk participants ( n = 181) and demonstrated preliminary support for the reliability and validity of the FFZI in an online, community sample. Ultimately, these data suggest that the FFZI is a useful measure of SZD PD and provide further evidence that SZD PD can be conceptualized as a maladaptive extension of introversion traits.