Measures Of Psychosis Proneness Research Articles

P603. The Working Memory Effect of Dexamphetamine Associates With Changes in Schizotypy Score

A deficit in working memory (WM) is one of the more robust cognitive findings in some people with schizophrenia. Evidence indicates that schizophrenia is associated with both increased dopamine (DA) release and WM deficits, and it has been shown that increasing dopamine release to abnormally high levels impairs WM in non-human primates. The present study aimed to examine the influence of dexamphetamine (DEX, 0.45 mg/kg, PO), DA releasing stimulant, on verbal WM (VWM) and spatial WM (SWM). The study also aimed to examine the influence of DEX on measures of psychosis-proneness (schizotypy) in healthy volunteers and the association of DEX-induced schizotypy and WM.

Atypical attentional filtering of visual information in youth with chromosome 22q11.2 deletion syndrome as indexed by event-related potentials

BackgroundYouth with chromosome 22q11.2 deletion syndrome (22q) face one of the highest genetic risk factors for the development of schizophrenia. Previous research suggests impairments in attentional control and potential interactions with elevated anxiety and reduced adaptive functioning may increase the risk for developing psychosis in this population. Here, we examined how variations in attentional control relate to the presence or severity of psychosis-proneness symptoms in these individuals. MethodsTo achieve this, we measured attentional control in youth (12–18 years) with 22q (N = 35) compared to a typically developing group (N = 45), using a flanker task (the Distractor Target task) while measuring neural activity with event-related potentials. ResultsSimilar to previous findings observed in people with schizophrenia, greater attentional capture by, and reduced suppression of, non-target flanker stimuli characterized participants with 22q and was indexed by the N2pc (N2-posterior-contralateral) and PD (distractor positivity) components. Although we observed no relationships between these components and measures of psychosis-proneness in youth with 22q, these individuals endorsed a relatively low incidence of positive symptoms overall. ConclusionsOur results provide neural evidence of an attentional control impairment in youth with 22q that suggests these individuals experience sustained attentional focus on irrelevant information and reduced suppression of distracting stimuli in their environment. Impairments in attentional control might be a valid biomarker of the potential to develop attenuated positive symptoms or frank psychosis in high-risk individuals long before the age at which such symptoms typically arise. The evaluation of such a hypothesis, and the preventive potential for the putative biomarker, should be the focus of future studies.

Toward incorporating genetic risk scores into symptom networks of psychosis.

Psychosis spectrum disorder is a heterogeneous, multifactorial clinical phenotype, known to have a high heritability, only a minor portion of which can be explained by molecular measures of genetic variation. This study proposes that the identification of genetic variation underlying psychotic disorder may have suffered due to issues in the psychometric conceptualization of the phenotype. Here we aim to open a new line of research into the genetics of mental disorders by explicitly incorporating genes into symptom networks. Specifically, we investigate whether links between a polygenic risk score (PRS) for schizophrenia and measures of psychosis proneness can be identified in a network model. We analyzed data from n = 2180 subjects (controls, patients diagnosed with a non-affective psychotic disorder, and the first-degree relatives of the patients). A network structure was computed to examine associations between the 42 symptoms of the Community Assessment of Psychic Experiences (CAPE) and the PRS for schizophrenia. The resulting network shows that the PRS is directly connected to the spectrum of positive and depressive symptoms, with the items conspiracy and no future being more often located on predictive pathways from PRS to other symptoms. To our knowledge, the current exploratory study provides a first application of the network framework to the field of behavior genetics research. This allows for a novel outlook on the investigation of the relations between genome-wide association study-based PRSs and symptoms of mental disorders, by focusing on the dependencies among variables.

Factor mixture analysis of paranoia in young people.

Paranoid thoughts are relatively common in the general population and can increase the risk of developing mental health conditions. In this study, we investigate the latent structure of paranoia in a sample of young people. Cross-sectional survey; 243 undergraduate students (males: 44.9%) aged 24.3years (SD 3.5). The participants completed the Green et al. Paranoid Thought Scales GPTS, a 32-item scale assessing ideas of social reference and persecution; the 12-item General Health Questionnaire (GHQ-12), and the 74-item Schizotypal Personality Questionnaire (SPQ). Confirmatory factor analysis (CFA) was used to confirm the two-factor structure of the GPTS. Factor mixture modeling analysis (FMMA) was applied to map the best combination of factors and latent classes of paranoia. The GPTS showed excellent internal reliability and test-retest stability. Convergent validity was good, with stronger links with measures of ideas of reference and of suspiciousness than with other measures of psychosis-proneness. CFA showed excellent fit for the two-factor solution. FMMA retrieved a three-class solution with 176 subjects (72.5%) assigned to a baseline class, 54 (22.2%) to a "suspicious and mistrustful" class, and 13 (5.3%) to a "paranoid thinking" class. Compared to the baseline class, the other two classes had a higher risk of psychological distress and psychosis-proneness. The latent structure of paranoid thinking in young people appears dimensional. Although caution is advised when generalizing from studies on college students, screening for paranoid ideation in young people who complain about psychological distress might prove useful to prevent the development of severe and potentially debilitating conditions.

Genome-Wide Association Study of Psychosis Proneness in the Finnish Population.

The current study examined quantitative measures of psychosis proneness in a nonpsychotic population, in order to elucidate their underlying genetic architecture and to observe if there is any commonality to that already detected in the studies of individuals with overt psychotic conditions, such as schizophrenia and bipolar disorder. Heritability, univariate and multivariate genome-wide association (GWAs) tests, including a series of comprehensive gene-based association analyses, were developed in 4269 nonpsychotic persons participating in the Northern Finland Birth Cohort 1966 study with information on the following psychometric measures: Hypomanic Personality, Perceptual Aberration, Physical and Social Anhedonia (also known as Chapman's Schizotypia scales), and Schizoidia scale. Genome-wide genetic data was available for ~9.84 million SNPs. Heritability estimates ranged from 16% to 27%. Phenotypic, genetic and environmental correlations ranged from 0.04-0.43, 0.25-0.73, and 0.12-0.43, respectively. Univariate GWAs tests revealed an intronic SNP (rs12449097) at the TMC7 gene (16p12.3) that significantly associated (P = 3.485 × 10-8) with the hypomanic scale. Bivariate GWAs tests including the hypomanic and physical anhedonia scales suggested a further borderline significant SNP (rs188320715; P-value = 5.261 × 10-8, ~572 kb downstream the ARID1B gene at 6q25.3). Gene-based tests highlighted 20 additional genes of which 5 had previously been associated to schizophrenia and/or bipolar disorder: CSMD1, CCDC141, SLC1A2, CACNA1C, and SNAP25. Altogether the findings explained from 3.7% to 14.1% of the corresponding trait heritability. In conclusion, this study provides preliminary genomic evidence suggesting that qualitatively similar biological factors may underlie different psychosis proneness measures, some of which could further predispose to schizophrenia and bipolar disorder.

SU54. Shared Architecture of Dimensional Psychotic Symptoms Across Psychosis Spectrum Disorders: Impact on Functional Outcomes and Neurocognition

Abstract Background: Psychosis spectrum disorders share significant overlap in symptoms, biomarkers, genetic factors, outcomes, and treatment response. Moreover, within each disorder, there is significant heterogeneity in symptom profiles, neurocognitive, and everyday functioning. This has lead to recent efforts, in line with the Research Domain Criteria (RDoC), to develop novel classifications based on dimensions that cut across traditional diagnostic boundaries. Whether there are homogeneous subgroups in bipolar disorder (BD) with distinct psychotic symptom profiles is unknown. Moreover, the impact of these subgroups on neurocognitive and everyday functioning is also unknown. We aimed to (1) cluster BD patients in homogeneous subgroups based on psychotic symptom profiles; (2) describe clinical, neurocognitive, and functional characteristics of each subgroup; and (3) test whether the subgroups extend across the psychosis spectrum (to patients with schizotypal personality disorder, SPD). Methods: Sample: 138 patients with BD I or II; 282 patients with SPD. Diagnosis: SCID, SIDP-IV. Psychotic symptoms: Schizotypal Personality Questionnaire, SPQ; a multidimensional measure of psychosis proneness that captures the full range from normal to abnormal, including subthreshold symptoms. Neurocognition: MATRICS Consensus Cognitive Battery (MCCB); Disability: World Health Organization Disability Assessment Schedule (WHODAS-II). With hierarchical cluster analyses, we tested for homogeneous subgroups in each sample (BD, SPD patients) based on the 9 SPQ subscales. To determine the impact of psychosis symptom profile on outcome, we used ANOVAs to compare the clusters on neurocognitive and everyday functioning. Results: In BD, we identified 3 clusters: (1) high propensity to positive symptoms, with significantly higher scores on ideas of reference, suspiciousness, unusual perceptions, odd beliefs, odd behavior, and odd speech than the other 2 clusters; (2) high negative symptoms and social dysfunction, with high scores on excess social anxiety and lack of friends; and (3) mild psychosis symptom profile, with the lowest scores across all SPQ subscales. Subgroup 1 (high positive symptoms) scored significantly lower in all cognitive areas (MATRICS composite, F = 3.72; df = 2; P = .027) and had lower premorbid IQ (F = 5.6; df = 124; P = .005) and significantly higher disability (WHODAS, F = 9.19; df = 2; P < .001) compared with the other 2 subgroups. In the SPD sample, we found a subgroup structure that was highly consistent with that described above. Conclusion: Our finding of a common structure of psychotic symptom profiles across different psychosis spectrum disorders supports the dimensional nature of the propensity to positive symptoms in a continuum across diagnostic boundaries. Our results further highlight the potential implications that this classification system may have on outcome.

Brain structural correlates of schizotypy and psychosis proneness in a non-clinical healthy volunteer sample

Schizotypal traits are phenotypic risk factors for schizophrenia, associated with biological changes across a putative schizophrenia spectrum. In this study, we tested the hypothesis that brain structural changes in key brain areas relevant to this spectrum (esp. medial and lateral prefrontal cortex) would vary across different degrees of schizotypal trait expression and/or phenotypic markers of psychosis proneness in healthy non-clinical volunteers. We analysed high-resolution 3Tesla magnetic resonance images (MRI) of 59 healthy volunteers using voxel-based morphometry (VBM), correlating grey matter values to the positive and negative symptom factors of the schizotypal personality questionnaire (SPQ, German version) and a measure of psychosis proneness (community assessment of psychic experiences, CAPE). We found positive correlations between positive SPQ dimension and bilateral inferior and right superior frontal cortices, and positive CAPE dimension and left inferior frontal cortex, as well as CAPE negative dimension and right supplementary motor area (SMA) and left inferior parietal cortex. However, only the positive correlation of the right precuneus with negative schizotypy scores was significant after FWE correction for multiple comparisons. Our findings confirm an effect of schizotypal traits and psychosis proneness on brain structure in healthy subjects, providing further support to a biological continuum model.

Dopaminergic basis of the psychosis-prone personality investigated with functional magnetic resonance imaging of procedural learning.

Previous evidence shows a reliable association between psychosis-prone (especially schizotypal) personality traits and performance on dopamine (DA)-sensitive tasks (e.g., prepulse inhibition and antisaccade). Here, we used blood oxygen level-dependent (BOLD) fMRI and an established procedural learning (PL) task to examine the dopaminergic basis of two aspects of psychosis-proneness (specific schizotypy and general psychoticism). Thirty healthy participants (final N = 26) underwent fMRI during a blocked, periodic sequence-learning task which, in previous studies, has been shown to reveal impaired performance in schizophrenia patients given drugs blocking the DA D2 receptor subtype (DRD2), and to correspond with manipulation of DA activity and elicit fronto-striatal-cerebellar activity in healthy people. Psychosis-proneness was indexed by the Psychoticism (P) scale of the Eysenck Personality Questionnaire-Revised (EPQ-R; 1991) and the Schizotypal Personality Scale (STA; 1984). EPQ-R Extraversion and Neuroticism scores were also examined to establish discriminant validity. We found a positive correlation between the two psychosis-proneness measures (r = 0.43), and a robust and unique positive association between EPQ-R P and BOLD signal in the putamen, caudate, thalamus, insula, and frontal regions. STA schizotypy score correlated positively with activity in the right middle temporal gyrus. As DA is a key transmitter in the basal ganglia, and the thalamus contains the highest levels of DRD2 receptors of all extrastriatal regions, our results support a dopaminergic basis of psychosis-proneness as measured by the EPQ-R Psychoticism.

Assessing Anomalous Perceptual Experiences in Nonpsychiatric Individuals and Outpatients with Psychosis in Taiwan: An Investigation Using the Cardiff Anomalous Perceptions Scale (CAPS)

The Cardiff anomalous perceptions scale (CAPS) has been recently designed for the assessment of anomalous perceptual experiences in the general population, and includes dimensions that measure distress, intrusiveness, and frequency. The purpose of this study was to assess the psychometric properties of a Taiwanese version of the CAPS. The English version of the CAPS was translated into Taiwanese (CAPS-T) and the latter was applied to this study. We administered the questionnaire to a consecutive sample of 192 participants with (n=106; clinical group including schizophrenia and affective psychosis) or without psychotic disorders (n=86; non-clinical group). In addition to the CAPS-T, the Taiwanese version of the brief psychiatric symptom rating scale (BSRS) measured the severity of the psychopathology. We also tested the psychometric properties of the CAPS-T including construct validity, internal consistency, test-retest reliability, and convergent and discriminative validity. Overall, the CAPS-T showed good construct validity, internal consistency, and stability over time and correlated significantly with the psychoticism subscale of the BSRS. As predicted, the mean differences in CAPS-T scores between participants with or without a psychotic disorder were significant. Convergent and discriminative validity were satisfactory. A score of 5 was found to the best threshold in discriminating between clinical and non-clinical samples. Our findings indicate that the Taiwanese version of the CAPS is a reliable and valid instrument to measure the multidimensionality of perceptual anomalies in general and appears to complement the clinical measures of psychosis proneness in Taiwan.

DISC1 Conditioned GWAS for Psychosis Proneness in a Large Finnish Birth Cohort

BackgroundGenetic evidence implicates the DISC1 gene in the etiology of a number of mental illnesses. Previously, we have reported association between DISC1 and measures of psychosis proneness, the Revised Social Anhedonia Scale (RSAS) and Revised Physical Anhedonia Scale (RPAS), in the Northern Finland Birth Cohort 1966 (NFBC66). As part of the studies of this Finnish birth cohort genome-wide association analysis has recently been performed.MethodologyIn the present study, we re-analyzed the genome-wide association data with regard to these two measures of psychosis proneness, conditioning on our previous DISC1 observation. From the original NFBC66 sample (N = 12 058), 4 561 individuals provided phenotype and genotype data. No markers were significant at the genome-wide level. However, several genes with biological relevance to mental illnesses were highlighted through loci displaying suggestive evidence for association (≥3 SNP with P<10E-4). These included the protein coding genes, CXCL3, KIAA1128, LCT, MED13L, TMCO7, TTN, and the micro RNA MIR620.ConclusionsBy conditioning a previous genome-wide association study on DISC1, we have been able to identify eight genes as associating to psychosis proneness. Further, these molecules predominantly link to the DISC1 pathway, strengthening the evidence for the role of this gene network in the etiology of mental illness. The use of quantitative measures of psychosis proneness in a large population cohort will make these findings, once verified; more generalized to a broad selection of disorders related to psychoses and psychosis proneness.

The Aberrant Salience Inventory: A new measure of psychosis proneness.

Aberrant salience is the unusual or incorrect assignment of salience, significance, or importance to otherwise innocuous stimuli and has been hypothesized to be important for psychosis and psychotic disorders such as schizophrenia. Despite the importance of this concept in psychosis research, no questionnaire measures are available to assess aberrant salience. The current research describes 4 studies designed to develop and validate the Aberrant Salience Inventory (ASI) as a measure of aberrant salience. In Study 1, an overinclusive item pool was subjected to an exploratory factor analysis, and items were kept or discarded based on factor loadings. In Study 2, the 5-factor structure of the ASI was confirmed with a confirmatory factor analysis, and a 2nd-order factor analysis found evidence consistent with a single higher order factor. Study 2 also provided support for the scale score's convergent validity as the ASI was strongly associated with psychosis-proneness measures and dissociation measures and moderately correlated with measures associated with levels of dopamine. This study also provided support for its discriminant validity as the ASI was only weakly associated with social anhedonia. Study 3 found that participants with elevated psychosis proneness had increased ASI scores, but in contrast, participants with elevated social anhedonia had similar scores to comparison participants. Finally, Study 4 found that participants with a history of psychosis had elevated ASI scores compared to a psychiatric comparison group. Overall, the ASI demonstrated sound psychometric properties and may be useful for measuring aberrant salience and psychosis proneness in clinical and nonclinical samples.

Confirmation of a four-factor structure of the Schizotypal Personality Questionnaire among undergraduate students

Objective Although several exploratory and confirmatory factor analyses have supported the initially proposed factor structure of the Schizotypal Personality Questionnaire (SPQ) in which its nine subscales are grouped into cognitive–perceptual, interpersonal, and disorganized domains, others have revealed different latent structures. This study determined the best-fitting factor structure from among five models that have been proposed in the literature, as well as five additional hierarchically related models. Methods Undergraduate college students ( n = 825) completed the SPQ as well as the Perceptual Aberration Scale (PAS) and the Revised Social Anhedonia Scale (SAS). Confirmatory factor analyses involving the nine SPQ subscales were conducted using the Linear Structural Relations Program ( LISREL 8.72). Results The best fitting model was a previously described 4-factor model including cognitive–perceptual, paranoid, negative, and disorganized domains. Correlations between the derived SPQ domains and the PAS score ranged r = .26–.39, and correlations between the SPQ domains and the SAS ranged r = .07–.41. Conclusions The present findings support a 4-factor model over the standard 3-factor model that is typically used to derive SPQ subscale scores. The four derived domains are minimally to moderately correlated with other measures of psychosis-proneness.

Hallucinatory Experiences, Delusional Thought Proneness, and Psychological Distress in a Nonclinical Population

Despite evidence that the reporting of delusion-like or hallucinatory experiences are predictive of the future development of a mental disorder in the spectrum of psychosis, the exact nature of such a kind of unusual subjective experience in the general population is still disputed. We investigated the multidimensionality of these experiences with the Peters et al. Delusions Inventory (PDI) and a modified Italian version of the Launay-Slade Hallucination Scale (LSHS-R) in 250 subjects of both genders drawn from the normal population, using the General Health Questionnaire (GHQ) as a measure of psychic distress of a clinically relevant nature. We found that GHQ scores are positively related to both the PDI and the LSHS-R scores, but the GHQ did not act as a mediator in the links between the 2 psychosis-proneness measures. Conversely, the LSHS-R scores fully mediated the links between GHQ and PDI scores. It can be argued that hallucination proneness and psychosis proneness do not overlap in the nonclinical population but can both cause distress separately.

The Ambiguous Intentions Hostility Questionnaire (AIHQ): A new measure for evaluating hostile social-cognitive biases in paranoia

Introduction. This study reports on the development of a new measure of hostile social-cognitive biases for use in paranoia research, the Ambiguous Intentions Hostility Questionnaire (AIHQ). The AIHQ is comprised of a variety of negative situations that differ in terms of intentionality. Items were developed to reflect causes that were ambiguous, intentional, and accidental in nature. Methods. Participants were 322 college students who completed the AIHQ along with measures of paranoia, hostility, attributional style, and psychosis proneness. The reliability and validity of the AIHQ was evaluated using both correlational and multiple regression methods. Results. The AIHQ had good levels of reliability (internal consistency and interrater reliability). The AIHQ was positively correlated with paranoia and hostility and was not correlated with measures of psychosis proneness, which supported the convergent and discriminant validity of the scale. In addition, the AIHQ predicted incremental variance in paranoia scores as compared to the attributional, hostility, and psychosis proneness measures. Ambiguous items showed the most consistent relationships with paranoia. Conclusions. The AIHQ appears to be a reliable and valid measure of hostile social cognitive biases in paranoia. Recommendations for using the AIHQ in the study of paranoia are discussed.

Slow habituation of arousal associated with psychosis proneness

Previous studies report skin conductance (SC) abnormalities in both patients with schizophrenia and psychosis-prone individuals. However, no studies have assessed SC abnormalities in relation to specific psychotic and emotional symptoms. The aim of the present study was to examine the relationship between SC orienting response and hallucination proneness, delusional ideation, anxiety and self-focused attention in non-clinical individuals. Forty-three participants were recruited and divided into two groups depending upon the SC habituation profile. Normal habituators (n=28) and slow habituators (n=15) were compared on measures of psychosis proneness, anxiety and self-focused attention. Slow habituators had significantly higher levels of delusional ideation and hallucination proneness than the normal habituators. SC habituation scores were particularly associated with the conviction of delusional ideas. Levels of anxiety or self-focused attention did not differ significantly between the groups. The study provides evidence of 'aetiological continuity'. Common mechanisms may contribute to psychotic experiences in non-clinical and clinical samples, consistent with the notion of a psychosis continuum.

Personality Correlates of Prepulse Inhibition of the Startle Reflex at Three Lead Intervals

Abstract The acoustic startle reflex (ASR) is modulated by a number of experimental factors, the most important of which in the field of psychopathology is weak prestimulation: The ASR is reliably reduced if preceded briefly by a weaker stimulus (i. e., the prepulse), an effect known as prepulse inhibition (PPI). PPI is thought to reflect centrally-mediated sensorimotor gating of stimuli, preventing cognitive overload and behavioural confusion. PPI is impaired in a variety of psychiatric disorders, notably schizophrenia, as well as in individuals who score high on psychometric measures of psychosis proneness. Two experiments examined the association of personality (trait emotionality) and PPI at three prepulse-to-pulse intervals (30, 60 and 120 ms). Consistent with previous reports, findings from both experiments showed highly significant PPI (defined as percentage reduction in the amplitude of the ASR), which increased with prepulse-to-pulse interval (30 &lt; 60 &lt; 120 ms). A novel finding was that, in both experiments 1 (N = 36) and 2 (N = 63), the trait of neuroticism was negatively correlated with PPI; in addition, a measure of positive incentive motivation (i. e., Behavioural Activation System, Drive subscale; BAS-Drive) was also negatively correlated with PPI. These trait emotionality associations were independent of gender. Possible causal explanations of these personality associations are outlined. It is concluded that, in order to clarify the aetiological role of sensorimotor gating in psychopathological conditions (e. g., schizophrenia, often entailing emotional activation), trait emotionality variance should be routinely examined in future PPI studies.

Developmental instability and schizotypy

Introduction. It has been suggested that evidence of developmental disturbance of cognition and lateralisation in schizophrenia can be best understood from the perspective of developmental stability (DS), an indicator of the extent to which an individual develops according to a specified ontogenic programme in the presence of environmental noise. Higher levels of fluctuating asymmetry (FA; the difference between right and left side of a quantitative morphological trait such as dermatoglyphics) are thought to reflect less DS. We examined this issue for dimensions of schizotypy. Methods. Associations between FA, measures of laterality and cognitive function on the one hand, and negative and positive dimensions of schizotypy on the other, were examined in a sample of 260 healthy adolescents aged 11.9–15.6 years. FA was measured as a–b ridge count right–left differences. Neuropsychological measures yielded a general cognitive ability score and a frontal function score. Laterality was assessed with the Annett scale. Results. Measures of psychosis proneness were normally distributed. Negative schizotypy was associated with more FA and lower general cognitive ability in a dose–response fashion. The association with FA was more apparent in boys. No associations existed with laterality or frontal function. Conclusion. The negative dimension of schizotypy may be associated with early developmental instability, resembling the pattern seen in the negative symptom dimension of schizophrenia. Measures of fluctuating asymmetry may be more sensitive with regard to the schizotypy phenotype than measures of laterality.

Schizotypal traits in relation to cerebellar volume and asymmetry: A high-resolution 3D magnetic resonance imaging study

The relationships between several indices of psychosis proneness and bilateral electrodermal orienting were examined in a large group of normal subjects and a heterogeneous group of schizophrenic patients. In the normal group, the Cognitive Disorganisation scale was characterised by shorter latencies and more irregular patterns of responding that may indicate greater disinhibitory processing in the regulation of attentional mechanisms. The Unusual Experiences scale and paranoia (both measures of positive or `active' schizotypy) were associated with a predominance of left hemisphere influences in normal female controls. High Introvertive Anhedonia scores predicted non-responding status in schizophrenic patients and hypo-responsivity in normal controls in support of some previous studies. Overall the results support the specificity and validity of different measures of psychosis proneness and the utility of psychophysiological investigation beyond the psychotic disorders themselves. © 1997 Elsevier Science B.V.

Vocational interests and career indecision among psychosis-prone college students.

This study investigated the relationship between scores on scales that purport to measure psychosis-proneness and scores on vocational interests, identity, and differentiation scales in a sample of 233 college students who completed the Perceptual Aberration and Magical Ideation scales, the Strong Campbell Interest Inventory, and the Career Decision Scale. The present findings are consistent with prior work indicating a sex-related association of scores on measures of psychosis-proneness and vocational interests. A positive correlation between scores on vocational indecision and measures of psychosis-proneness was also found, suggesting that both men and women who score high on psychosis-proneness find it difficult to formulate long-term career goals. Finally, there was no significant correlation between scores on measures of psychosis-proneness and Holland's Vocational Differentiation Index. Present results are discussed in light of previously reported sex differences among psychosis-prone adults and diagnosed schizophrenics. The implications of the findings for vocational counselors are also addressed.

Electrodermal relationships with personality measures of psychosis-proneness in psychotic and normal subjects

The relationships between several indices of psychosis proneness and bilateral electrodermal orienting were examined in a large group of normal subjects and a heterogeneous group of schizophrenic patients. In the normal group, the Cognitive Disorganisation scale was characterised by shorter latencies and more irregular patterns of responding that may indicate greater disinhibitory processing in the regulation of attentional mechanisms. The Unusual Experiences scale and paranoia (both measures of positive or `active' schizotypy) were associated with a predominance of left hemisphere influences in normal female controls. High Introvertive Anhedonia scores predicted non-responding status in schizophrenic patients and hypo-responsivity in normal controls in support of some previous studies. Overall the results support the specificity and validity of different measures of psychosis proneness and the utility of psychophysiological investigation beyond the psychotic disorders themselves. © 1997 Elsevier Science B.V.