Schizophrenia spectrum personality disorders in psychometrically identified schizotypes at two-year follow-up.

Earlier (Bolinskey et al., 2015), we reported that psychometrically identified schizotypes displayed greater symptom levels and higher incidences of schizophrenia spectrum (schizotypal, schizoid, paranoid, and avoidant) personality disorders (PDs). In this study, 49 schizotypes and 39 matched controls participated in follow-up assessments after two years. Participants were previously identified as schizotypes or controls based on scores on the Chapman Psychosis Proneness Scales (CPPS), and were interviewed at baseline and follow-up with the Personality Disorder Interview for DSM-IV (PDI-IV). At follow-up, schizotypes displayed significantly higher symptom levels compared to controls, with medium to large effects, and appeared to meet criteria for diagnosis of each PD more often than controls, although significant differences were only observed for paranoid PD. Overall, schizotypes were more likely to have met criteria for a diagnosis at either baseline or follow-up. Finally, we observed a widening disparity over time between schizotypes and controls in avoidant and schizoid PDs. These results suggest that schizophrenia spectrum PDs, as well as subthreshold symptoms of these disorders, can represent a greater liability for schizophrenia in individuals identified as at-risk on the basis of psychometric means only. Furthermore, these findings demonstrate that such differences persist, and in some cases increase, over time.

Further examination of the factor structure of the Chapman Psychosis Proneness Scales (CPPS).

Results of recent analyses of the Chapman Psychosis Proneness Scales (CPPS) have been inconsistent with regard to their factor structure. This inconsistency has involved whether the Revised Social Anhedonia Scale (SocAnh) reflects only the negative or both the negative and positive dimensions of schizotypy, along with the degree of correlation between these two dimensions. In the present study, confirmatory factor analysis was used to compare models created by Chan et al. and Kwapil et al.; a third model was constructed based on adjustments to these prior models and consideration of the schizotypy construct. Following Kwapil et al., our model allowed for bi-loading of SocAnh scale, but eliminated the correlation between positive and negative factors. Although fitness for each of the previously offered models was adequate, RMSEA and chi-square indicators suggested ideal fit for the model proposed by Kwapil and our new model, which redirects variance thought to be shared among the positive and negative dimensions to its specific source, SocAnh. The implications of these competing models with regard to our conceptualization of schizotypy are addressed. It is suggested that the cross loading of SocAnh reflects the notion of social anhedonia as the core of schizotypic personality organization.

Revisiting the blurry boundaries of schizophrenia: spectrum disorders in psychometrically identified schizotypes.

Certain Personality Disorders (PDs) have been found to be present in the prodromal phase of schizophrenia at a higher rate than other personality disorders. Although schizotypal, paranoid, and schizoid PDs are traditionally viewed as spectra for schizophrenia, research suggests that avoidant PD should be included in this group (e.g., Fogelson et al., 2007). The present study examines whether a sample of psychometrically identified schizotypes (SZT) have higher incidence of schizophrenia-spectrum PDs, as well as more symptoms of these PDs, in general, than does a matched comparison (MC) sample. Eighty-five SZT and 78 MC participants were administered the Personality Disorder Interview for DSM-IV (PDI-IV) to assess PD symptoms and diagnoses. Results indicate that the SZT group evidenced significantly more symptoms of avoidant, schizoid, paranoid, and schizotypal PDs than did the MC group. Further, there were significant differences in the incidence of these PDs between the groups.

Using the MMPI-2-RF to discriminate psychometrically identified schizotypic college students from a matched comparison sample.

This study investigates the extent to which the Minnesota Multiphasic Personality Inventory-2 Restructured Form (MMPI-2-RF) profiles of 52 individuals making up a psychometrically identified schizotypes (SZT) sample could be successfully discriminated from the protocols of 52 individuals in a matched comparison (MC) sample. Replication analyses were performed with an additional 53 pairs of SZT and MC participants. Results showed significant differences in mean T-score values between these 2 groups across a variety of MMPI-2-RF scales. Results from discriminant function analyses indicate that schizotypy can be predicted effectively using 4 MMPI-2-RF scales and that this method of classification held up on replication. Additional results demonstrated that these MMPI-2-RF scales nominally outperformed MMPI-2 scales suggested by previous research as being indicative of schizophrenia liability. Directions for future research with the MMPI-2-RF are suggested.

Season of birth, mixed-handedness, and psychometric schizotypy: preliminary results from a prospective study.

Season of birth and hand preference were examined in a sample of 42 (7 males, 35 females) individuals who were identified as schizotypic based on their scores on selected scales of the Chapman Psychosis Proneness Scales (CPPS) and a matched comparison sample of 42 individuals with non-deviant CPPS scores. Presence or absence of schizotypy was analyzed using chi square tests of independence with the presence or absence of each risk factor serving as the independent variable. Further analyses incorporated independent means t tests to examine mean scores on the CPPS with the presence or absence of each risk factor again serving as the independent variable. Results supported the hypothesis that winter/early-spring birth would be associated with psychometric schizotypy, although the results for mixed-handedness fell just short of statistical significance. However, mixed hand preference was associated with higher scores on MagId and PerAb scales of the CPPS, but not the RSA scale, which suggests that mixed laterality is associated with the more cognitive-perceptual aspects of schizotypy. Results are discussed in relation to previous literature and their relevance to the prediction of schizophrenia-related psychosis.

Premorbid personality indicators of schizophrenia-related psychosis in a hypothetically psychosis-prone college sample.

Research into psychosis proneness has established the Chapman Psychosis Proneness Scales (CPPS), certain personality disorders, certain response patterns on the MMPI-2, and social withdrawal as being valid indicators of liability. The current study extends our understanding of premorbid indicators of schizophrenia-related psychosis (SRP) by examining whether individuals identified as hypothetically psychosis prone (HPP) by virtue of their CPPS scores also show differences on other premorbid indicators of SRP. Results indicate that HPP individuals evidence more deviancy in the schizophrenic direction. By providing additional construct validity for the CPPS and other endophenotypic indicators of premorbid processes, strategies for understanding the development of SRP are enhanced.

Sources of individual differences in stressful life event exposure in male and female twins.

The roles of genetic and environmental influences on stressful life events were examined in 3938 twin pairs (MZ, same-sex DZ, and opposite-sex DZ) using a sex-limitation model. Life events were assessed by personal interview, and were categorized as being either personal (i.e., events that occur directly to the individual) or network (i.e., events that occur to someone within the individual's social network, thus affecting the individual indirectly). Consistent with previous reports, genetic factors were found to exert more influence on personal events than network events. Genetic correlations between males and females suggest that many of the same genetic factors are acting within both genders.

A replication of the MMPI-A PSY-5 scales and development of facet subscales.

McNulty, Harkness, Ben-Porath and Williams recently developed Personality Psychopathology Five (PSY-5) scales for the Minnesota Multiphasic Personality Inventory-A (MMPI-A). This study examined these new scales in a sample of 545 adolescents receiving inpatient psychiatric treatment. Item-level principal components analyses were employed to determine the internal structure of each PSY-5 scale and to aid in the creation of facet subscales for each PSY-5 scale. Results suggest that the MMPI-A PSY-5 scales display adequate internal consistency and our findings generally replicate the original work of McNulty et al. but also extend this work by showing that several of the PSY-5 scales may also be subdivided into meaningful lower level dimensions. These facet subscales for each of the MMPI-A PSY-5 scales are offered for further study.

MMPI-A characteristics of male adolescents in juvenile justice and clinical treatment settings.

The current study investigates the extent to which the Minnesota Multiphasic Personality Inventory-Adolescent (MMPI-A) profiles of 196 male adolescents evaluated in a South Carolina detention center could be successfully discriminated from the protocols of 200 male adolescent psychiatric inpatients in three states and 151 dually diagnosed male adolescents. Results showed significant differences in mean T-score values among these three groups of adolescents across a variety of MMPI-A scales and subscales. Results from discriminant function analyses indicate that treatment setting can be predicted effectively from MMPI-A profiles. Beyond the MMPI-A profile differences established for adolescents in these groups, the similarities of adolescents were also noted, particularly in terms of the frequent occurrence of Within-Normal-Limits profiles for adolescents in all groups. Potential directions for future research with the MMPI-A are presented.

The Schizophrenia Proneness (SzP) scale: an MMPI-2 measure of schizophrenia liability.

We examined the psychometric properties and construct validity for a Minnesota Multiphasic Personality Inventory-2 Schizophrenia Proneness (SzP) scale (Bolinskey et al., 2001) and provided normative statistics. Premorbid participants were offspring of parents with schizophrenia-related illness (SRI), with comparison groups of offspring of parents with major affective disorders and offspring of normals. Postmorbid participants were twins affected with SRI; their unaffected relatives served as a comparison group. Results suggest that an SzP T score of 65 or above is an effective indicator of personality processes associated with increased liability to developing SRI.

A factor structure for the MMPI-A: replication with male delinquents.

The Minnesota Multiphasic Personality Inventory-Adolescent (MMPI-A) Structural Summary was developed as a means of simplifying the interpretation of the 69 scales and subscales of this test instrument by organizing findings around eight primary factor dimensions. The current study examined the scale-level factor structure of the MMPI-A in a large sample of 1,610 male juvenile delinquents to assess the potential usefulness of this factor structure in a delinquency population. In this attempt to replicate the MMPI-A scale-level factor structure identified by Archer, Belevich, and Elkins in the MMPI-A normative sample and by Archer and Krishnamurthy in a clinical sample, a correlation matrix of all MMPI-A scale raw scores was created for a principal factor analysis. Results from the factor analysis produced a seven-factor solution that was largely consistent with the dimensions of the MMPI-A Structural Summary. Results were also reported in terms of the frequency of elevations on Structural Summary dimensions, with particular evidence of the importance of the Immaturity factor in describing this male juvenile delinquent sample.