A self-reported instrument for prodromal symptoms of psychosis: testing the clinical validity of the PRIME Screen-Revised (PS-R) in a Japanese population

OBJECTIVE: Early intervention for psychosis requires an easy, useful assessment instrument to identify subjects with prodromal symptoms at an early stage. The aim of this study was to test the clinical validity of the PRIME Screen-Revised (PS-R), a 12-item self-reported instrument for prodromal symptoms of psychosis, by comparing the results for a non-clinical population with those for a clinical population. METHOD: The PS-R was administered to 1,024 subjects (496 students and 528 outpatients). Of the 528 patients, 115 were randomly recruited and tested using the Structured Interview for Prodromal Syndromes (SIPS) to determine the concordant validity of the PS-R. The predictive validity of the PS-R was measured by determining the transition rate to psychosis during a 6-month follow-up period. RESULTS: The specificity and sensitivity of the PS-R, using the SIPS as a gold standard, were 0.74 and 1.00. The concordant validity of the PS-R against the SIPS was 0.43. The predictive validity of the PS-R and the SIPS, defined as the transition rate to psychosis, were 0.11 and 0.25, respectively. None of the patients with negative PS-R results developed psychosis. CONCLUSIONS: Our findings showed that the PS-R was highly valid and that its usage is feasible in both general practice and clinical settings. This self-reported instrument represents a useful screening tool for alerting clinicians to subjects with psychotic prodromal symptoms.     

Mental disorders and medical conditions. A community study in a small island in Spain

OBJECTIVES: This study focuses on the comorbidity between medical and psychiatric illnesses in a sample taken from the general population. METHODS: We design a two-stage epidemiological community study in the island of Formentera (Spain), using the Schedules for Clinical Assessment in Neuropsychiatry (SCAN). In the first stage, the sample (N=697) was screened using the General Health Questionnaire (GHQ-28). In the second stage, the SCAN, subjects' clinical histories and General Practitioners' diagnosis were used to evaluate psychiatric disorders and medical illnesses. The final sample comprised 242 subjects. RESULTS: Subjects with diagnosed ICD-10 mental disorders presented higher comorbidity with medical pathologies than the group of respondents without psychiatric diagnosis, although the differences were not statistically significant. Of the psychiatric conditions, mood disorders (in which differences were significant) and neurotic disorders were the ones that most frequently presented comorbidity, followed by sleep disorders. Mean scores on the GHQ-28 used at the screening stage, and mean scores on neurotic, depressive and somatic symptoms on the SCAN, were significantly higher in the comorbid group. Comorbidity was more frequent in females. CONCLUSION: More studies on comorbidity in general population are required, with diagnostic instruments that cover the whole of the psychiatric spectrum and correct assessment systems for medical diagnosis.     

The prodromal questionnaire (PQ): preliminary validation of a self-report screening measure for prodromal and psychotic syndromes

This study aims to establish preliminary validity of the Prodromal Questionnaire (PQ), a 92-item self-report screening measure for prodromal and psychotic symptoms. Adolescents and young adults (N = 113) referred to a prodromal psychosis research clinic completed the PQ and the Structured Interview for Prodromal Syndromes (SIPS [Miller, T.J., McGlashan, T.H., Woods, S.W., Stein, K., Driesen, N., Corcoran, C.M., Hoffman, R., Davidson, L., 1999. Symptom assessment in schizophrenic prodromal states. Psychiatric Quarterly 70(4), 273-287]), an interview with established validity for predicting future psychosis. When maximizing selection of true positive cases, scores on a subset of PQ items that assess positive symptoms predicted a concurrent prodromal or psychotic SIPS diagnosis with 90% sensitivity and 49% specificity. The PQ shows good preliminary validity in detecting individuals with an interview-diagnosed prodromal or psychotic syndrome, but it is less sensitive to the threshold between prodromal and full-blown psychosis.     

The prodromal questionnaire (PQ): preliminary validation of a self-report screening measure for prodromal and psychotic syndromes

This study aims to establish preliminary validity of the Prodromal Questionnaire (PQ), a 92-item self-report screening measure for prodromal and psychotic symptoms. Adolescents and young adults (N = 113) referred to a prodromal psychosis research clinic completed the PQ and the Structured Interview for Prodromal Syndromes (SIPS [Miller, T.J., McGlashan, T.H., Woods, S.W., Stein, K., Driesen, N., Corcoran, C.M., Hoffman, R., Davidson, L., 1999. Symptom assessment in schizophrenic prodromal states. Psychiatric Quarterly 70(4), 273-287]), an interview with established validity for predicting future psychosis. When maximizing selection of true positive cases, scores on a subset of PQ items that assess positive symptoms predicted a concurrent prodromal or psychotic SIPS diagnosis with 90% sensitivity and 49% specificity. The PQ shows good preliminary validity in detecting individuals with an interview-diagnosed prodromal or psychotic syndrome, but it is less sensitive to the threshold between prodromal and full-blown psychosis.     

Identification and characterization of prodromal risk syndromes in young adolescents in the community: a population-based clinical interview study

While a great deal of research has been conducted on prodromal risk syndromes in relation to help-seeking individuals who present to the clinic, there is a lack of research on prodromal risk syndromes in the general population. The current study aimed first to establish whether prodromal risk syndromes could be detected in non-help-seeking community-based adolescents and secondly to characterize this group in terms of Axis-1 psychopathology and general functioning. We conducted in-depth clinical interviews with a population sample of 212 school-going adolescents in order to assess for prodromal risk syndromes, Axis-1 psychopathology, and global (social/occupational) functioning. Between 0.9% and 8% of the community sample met criteria for a risk syndrome, depending on varying disability criteria. The risk syndrome group had a higher prevalence of co-occurring nonpsychotic Axis-1 psychiatric disorders (OR = 4.77, 95% CI = 1.81-12.52; P < .01) and poorer global functioning (F = 24.5, df = 1, P < .0001) compared with controls. Individuals in the community who fulfill criteria for prodromal risk syndromes demonstrate strong similarities with clinically presenting risk syndrome patients not just in terms of psychotic symptom criteria but also in terms of co-occurring psychopathology and global functioning.     

Validity and reliability of an inpatient severity of psychiatric illness measure

Inpatient psychiatric severity measures are often used but few psychometric data are available. This study evaluated the psychometric properties (reliability and validity) of a measure used to assess severity of psychiatric illness among inpatients. Using the severity measure, minimally trained raters conducted retrospective patient record reviews to assess medical necessity for psychiatric hospitalization. The data analysis compared 135 civilly committed psychiatric inpatients with a heterogeneous group of 248 psychiatric inpatients at a general hospital. The severity measure showed acceptable inter-rater reliability in both populations. Two-way analysis of variance showed that the intra-class correlation coefficient for the total score was 0.65 for general hospital subjects and 0.63 for civilly committed subjects. Differences in mean scores were substantial (15 out of a possible 75 points for general hospital subjects versus 42 for civilly committed subjects, Mann-Whitney U = 562, p < 0.001). As expected, all civilly committed subjects were well above admission cut-off score of 12, versus only 64% of the general hospital patients. The measure is appropriate for retrospective severity assessment and may also be useful for pre-admission screening.     

Retrospective parent report of psychiatric histories: do checklists reveal specific prodromal indicators for postpubertal‐onset pediatric bipolar disorder?

OBJECTIVES: This study retrospectively investigated the relationship between prodromal symptoms described in the literature for pediatric bipolar disorder (BD) and the diagnosis of BD by comparing adolescents with BD to those in control and attention-deficit hyperactivity disorder (ADHD) groups. METHODS: Semi-structured interviews [Schedule for Affective Disorders and Schizophrenia for School-Age Children - Present and Lifetime version (K-SADS-PL) and Washington University in St. Louis Kiddie Schedule for Affective Disorders and Schizophrenia (WASH-U-KSADS)] and checklists (Conners' Rating Scales and Child Behavior Checklist) identified participants (13-17 years) as either normal controls (NC; n = 28), ADHD (n = 29) or BD (n = 25). Bipolar disorder included BD I, BD II and BD not otherwise specified (NOS). Parents completed a widely used but unvalidated symptom checklist published by Papolos and Papolos (The Bipolar Child: the Definitive and Reassuring Guide to Childhood's Most Misunderstood Disorder) assessing across three developmental periods (preschool, latency, adolescence) for the presence/absence of psychiatric symptoms, many of which have been described in the literature as prodromal to the emergence of manic symptoms. RESULTS: While both clinical groups had more psychiatric symptoms than the NC group, more problems were reported in the ADHD group, most of which were symptoms seen as cardinal features of ADHD (e.g., being easily distracted, interrupting, having trouble concentrating). Differences were present by the latency period. Depressed mood was higher in the BD group during latency, and elated mood and fire-setting were higher in the BD group during adolescence. Results were more similar when comparing adolescents with BD only versus those with both ADHD and BD. Frequency of symptoms was comparable regardless of whether or not there was a family history of BD. Frequency of symptoms was also similar across the BD subtypes. CONCLUSIONS: Using retrospective parent report, a cluster of prodromal psychiatric symptoms specific to BD was not identified, which both questions the utility of a widely used yet unvalidated clinical scale and encourages caution when interpreting information collected via retrospective checklists. Although these data suggest that the presence of prodromal non-specific psychiatric symptoms flags a more global risk for psychopathology, significant limitations exist when using retrospective report and, as such, further prospective research is required to investigate the progression of psychiatric symptoms across childhood disorders.     

The Trail Making Test in prodromal Huntington disease: contributions of disease progression to test performance

We examined the Trail Making Test (TMT) in a sample of 767 participants with prodromal Huntington disease (prodromal HD) and 217 healthy comparisons to determine the contributions of motor, psychiatric, and cognitive changes to TMT scores. Eight traditional and derived TMT scores were also evaluated for their ability to differentiate prodromal participants closer to estimated age of diagnosis from those farther away and prodromal individuals from healthy comparisons. Results indicate that motor signs only mildly affected Part A, and psychiatric symptoms did not affect either part. Tests of perceptual processing, visual scanning, and attention were primarily associated with Part A, and executive functioning (response inhibition, set-shifting), processing speed, and working memory were associated with Part B. Additionally, TMT scores differentiated between healthy comparisons and prodromal HD individuals as far as 9-15 years before estimated diagnosis. In participants manifesting prodromal motor signs and psychiatric symptoms, the TMT primarily measures cognition and is able to discriminate between groups based on health status and estimated time to diagnosis.     

Validity of the mood disorder questionnaire: a general population study

OBJECTIVE: This study tested the validity in the adult general population of the Mood Disorder Questionnaire, a screening instrument for bipolar I and II disorders. The Mood Disorder Questionnaire has been validated in a psychiatric outpatient study group. METHOD: A total of 711 subjects (stratified by Mood Disorder Questionnaire score) were randomly selected from a group of 85,358 adult respondents in a nationwide epidemiological general population sample that was balanced for key demographic variables. Of these, 695 subjects received a telephone interview involving an abbreviated version of the Structured Clinical Interview for DSM-IV. RESULTS: A sensitivity of 0.281 and a specificity of 0.972 were obtained for the Mood Disorder Questionnaire. CONCLUSIONS: The Mood Disorder Questionnaire is a useful screening instrument for bipolar I and II disorders in the community. The operating characteristics of the Mood Disorder Questionnaire in the general population differ substantially from its characteristics in outpatient psychiatric settings.     

Self-report of attenuated psychotic experiences in a college population

This study assessed the rates of self-reported "prodromal" psychotic symptoms and related distress in a college population. 1020 students completed the Prodromal Questionnaire (PQ), a self-report screening measure for psychosis risk. Participants' responses were highly similar to the responses of non-psychotic-spectrum patients in the original PQ validation sample [Loewy, R.L., Bearden, C.E., Johnson, J.K., Raine, A., Cannon, T.D., 2005. The Prodromal Questionnaire (PQ): preliminary validation of a self-report screening measure for prodromal and psychotic syndromes. Schizophr. Res. 79 (1) 117-125], suggesting that the PQ may perform similarly with a variety of populations. Applying the cutoff proposed for screening treatment-seeking patients (8 or more positive symptoms) identified 43% of students, while comparatively fewer participants (25%) endorsed eight or more items at the frequency required for prodromal syndrome diagnosis by interview (i.e., weekly), and only 2% endorsed eight or more items as distressing. Although attenuated psychotic experiences are commonly reported by "normal" young adults, frequent and distressing items identify a proportion of students more consistent with the prevalence of psychotic-spectrum disorders in the general population, which suggests a potential for future screening of unselected samples.     

Young people at risk for psychosis: case finding and sample characteristics of the Oulu Brain and Mind Study

Aim: Set within the general population‐based Northern Finland Birth Cohort 1986, the Oulu Brain and Mind Study aims to explore the causes and pathogenesis of psychotic illness by following young people at risk for psychosis due to having a first‐degree relative with psychotic illness or due to having experienced psychotic‐like symptoms themselves. We report the study methods and explore the relationship between these definitions of high risk for psychosis and operational criteria for a prodromal psychosis syndrome based on interview. Methods: Prospectively collected data from earlier follow‐ups of this cohort were combined with health register data to categorize subjects as those with familial risk (n = 272), symptomatic risk (n = 117), psychosis (n = 78), attention deficit hyperactivity disorder (ADHD) (n = 103) and a sample of controls (n = 193) drawn randomly from the remaining cohort. The Structured Interview for Prodromal Syndromes (SIPS) was applied to all, 295 participants together with questionnaires measuring psychosis vulnerability and schizotypal traits. Results: There were 29 (10%) current prodromal cases. Criteria for the current prodromal syndrome were fulfilled by 12% of the familial risk group and 19% of the symptomatic risk group, compared with 5% of the ADHD group and 4% of controls. Conclusion: We successfully detected young people with a prodromal psychosis syndrome although relatively few subjects deemed to be at high risk met the full operational criteria according to the SIPS interview. Combining methods from familial, clinical and psychometric high‐risk approaches provides a tractable method for studying risk of psychosis in the general population.     

Sexual abuse and psychiatric symptoms in an epileptic population.

One hundred and seven consecutive patients attending the outpatient epilepsy clinic at a teaching general hospital were assessed by clinical interview for a history of sexual abuse. Questionnaires dealing with overall psychiatric symptomatology i.e., (SCL-90), (TSC-40) and depression (ZSRDS) were also used. The majority of subjects were single (60%), living at home (76.6%) and had an average age of 29 years. The mean duration of epilepsy was 18.8 years and the seizures were controlled with medication in 65.2% of patients. Ten (9.3%) of the subjects had been sexually abused. This frequency of sexual abuse is lower than in the general population and among psychiatric patients. The specific form of sexual abuse consisted of sexual intercourse (n = 4), fondling (n = 4) and oral sex (n = 2). The sexually abused subjects had significantly higher scores on the anxiety subscale of the SCL-90 and depression score on the ZSRDS than non-abused subjects.     

Reliability,validity and standardization of the Japanese version of the Social Adjustment Scale-Self Report

The purpose of the present paper was to examine the reliability and validity of the Japanese version of the Social Adjustment Scale-Self Report (SAS-SR) and to present its normative data. The SAS-SR was administered to a random sample of all the employees of a large general hospital, together with the General Health Questionnaire (n = 363). It was also administered to a representative subset of first-visit patients at 33 psychiatric hospitals and clinics from all over Japan, along with the semistructured psychiatric interview to ascertain the patients' diagnoses (n = 1581). For the internal consistency reliability of the subscales and the overall scale of the SAS-SR, Cronbach's alpha was between 0.61 and 0.73. The Pearson product-moment correlations between the subscale and overall scale scores with the GHQ score were mostly >0.3. The scores were statistically significantly and substantively different between the normal sample and the patient samples, and were also meaningful, differentiating between various diagnostic subgroups. The reference ranges of the SAS-SR scores for mentally healthy subjects were calculated as 95% prediction intervals; for example, 1.22-2.22 for the overall score. The Japanese version of the SAS-SR has good reliability and satisfactory validity. The present study provided reference ranges for its scores in order to increase their interpretability. With its ease of administration and its rich subscales, the scale promises to offer a psychometrically sound measure with which to assess social adjustment in people with various psychiatric disorders.     

The validity of questionnaire self-report of psychopathology and parent-child relationship quality in juvenile delinquents with psychiatric disorders

The present study focuses on the validity of questionnaire self-report of psychopathology and parent-child relationship quality for juvenile delinquents with severe behavioural and psychiatric disorders by comparing information derived from questionnaire self-report with information from other sources, including parent report, in-depth interviewing, behavioural observation by clinicians, and official criminal records. The sample consisted of N=33 juvenile delinquents with psychiatric disorders. The juvenile delinquents did not report increased levels of psychopathology or poor relationships with their parents, which is inconsistent with the fact that all juvenile delinquents were in day treatment for severe behavioural maladaptation and relationship problems. Moreover, parent ratings of psychopathology were consistently in the clinical range and relationship quality was evaluated as very poor by the parents (d>.80). We conclude that screening instruments for psychopathology and assessment of relationship quality relying on questionnaire self-report may not yield valid scores in this (extreme) population of juvenile delinquents.     

The relationship of neuroticism and extraversion to symptoms of anxiety and depression in the general population

Few studies have investigated the relationship of the personality dimensions of neuroticism and extraversion to the symptoms of depression and anxiety in the general population. A random general population sample (ages 20-70 years), from two Finnish cities was surveyed with the Eysenck Personality Inventory (EPI), Beck Depression Inventory (BDI), and Beck Anxiety Inventory (BAI). In addition, questions regarding diagnosed lifetime mental disorders, health care use for psychiatric reasons in the past 12 months, and history of mental disorders in first-degree relatives were posed. Among the 441 subjects who participated, neuroticism correlated strongly with symptoms of depression (r(s)=.71, P<.001) and anxiety (r(s)=.69, P<.001), and somewhat with self-reported lifetime mental disorder (r(s)=.30, P<.001) and health care use for psychiatric reasons in the past 12 months (r(s)=.24, P<.001). Extraversion correlated negatively with symptoms of depression (r(s)=-.47, P<.001), anxiety (r(s)=-.36, P<.001), self-reported lifetime mental disorder (r(s)=-.17, P<.001), and health care use for psychiatric reasons in the past 12 months (r(s)=-.14, P=.004). In multiple regression models, even after adjusting for gender, age, and education, BDI scores were significantly associated with neuroticism, extraversion, and age, whereas BAI scores were associated only with neuroticism. Neuroticism is strongly associated with depressive and anxiety symptoms, and intraversion is moderately associated with depressive symptoms in the urban general population. The relationship of these personality dimensions to both self-reported lifetime mental disorders and use of health services for psychiatric reasons strengthens the clinical validity of these personality dimensions.     

Symptoms of depression and posttraumatic stress disorder in an outpatient population before and after Hurricane Katrina

The aim of the present investigation was to evaluate symptoms of depression and posttraumatic stress disorder (PTSD) in an outpatient psychiatric population before and after Hurricane Katrina. The sample consisted of 156 patients (110 females; M(age)=41.2 years, SD=10.9) at an outpatient psychiatric clinic who completed measures of psychological symptoms as part of their regular clinical care in the month before (n=76; 49%) and the 1 month after (n=80; 51%) Hurricane Katrina made landfall. Partially consistent with prediction, depression scores were significantly higher in the month following the hurricane, but PTSD scores were not significantly different. Depressive symptoms after the hurricane were predicted by watching television coverage of the looting that occurred in New Orleans and by the amount of time the participant was without electricity. Symptoms of PTSD after the hurricane were predicted by the participants' use of general television viewing as a coping strategy, the amount of time they spent watching television coverage of the looting in New Orleans, and the use of prayer as a coping behavior. Of these variables, only prayer was associated with a decrease in PTSD symptoms. Findings are discussed in relation to the need for collaborative efforts between clinically oriented and research-oriented institutions to study the impact of large-scale disasters on a variety of populations.     

Schizotypal personality disorder or prodromal symptoms of schizophrenia?

Schizotypal personality disorder shares some attenuated phenotypic features with schizophrenia, but represents an independent syndrome. In contrast, prodromal symptoms of schizophrenia represent early warning signs of the impending onset of schizophrenia. Although these constructs are intended to reflect independent syndromes, self-report instruments measuring these constructs assess similar symptoms. It does not appear that existing research has examined the relative discriminant validity of screening instruments for these syndromes. A sample of 998 young adults (68% female; 73% Caucasian), within the age of risk for schizophrenia (ages 18–34; mean 20.4 ± 2.2), met validity criteria after completing online versions of the Abbreviated Schizotypal Personality Questionnaire (SPQ-B) and the 24-item Abbreviated Youth Psychosis at Risk Questionnaire (Y-PARQ-B). Based on clinical cut-off scores used in previous research, 5.2% were [only] considered at heightened risk for psychosis (potentially prodromal), 3.4% had [only] schizotypal personality features, and 2.9% met criteria for both constructs (75% of individuals meeting cutoff for one measure did not meet criteria for the other). Males and younger participants scored significantly higher on both measures. The total scores from the SPQ-B and Y-PARQ-B showed a significant positive correlation (r_s = .66, p < .001, R² = .43); however, 57% of the variance was not shared between the measures. Of the three SPQ-B subscales, Cognitive–Perceptual showed the strongest correlation with Y-PARQ-B. Results suggest that the SPQ-B and Y-PARQ-B have moderate discriminate validity between the overlapping, yet distinct, constructs of schizotypal personality and heightened risk of developing psychosis (potentially prodromal).     

Psychometric properties of a Persian-language version of the Beck Depression Inventory--Second edition: BDI-II-PERSIAN

The Beck Depression Inventory (BDI) is perhaps the most commonly used screening instrument for depression in the general population. We examined the psychometric properties of a Persian-language version of the second edition of this instrument (BDI-II) [Beck et al., 1996] in an Iranian college-student sample. In a sample of 125 student volunteers from two Iranian universities, we compared mean item scores on the BDI-II-Persian with those on the English-language version administered to North American college students, and assessed internal consistency and test-retest reliability of the BDI-II-Persian and its concurrent validity against a measure of negative automatic thoughts in depression, the Automatic Thoughts Questionnaire [Hollon and Kendall, 1980]. We also examined the factor structure of the BDI-II-Persian through comparing the fit of various proposed models to the data using confirmatory factor analysis. The BDI-II-Persian had high internal consistency (Cronbach's alpha=0.87) and acceptable test-retest reliability (r=0.74). The instrument correlated strongly with the Automatic Thoughts Questionnaire. In factor analysis, models with strongly correlated affective-cognitive and somatic-vegetative factors provided a better fit than models with one global factor. These data support the reliability and concurrent validity of the BDI-II-Persian as a measure of depressive symptoms in nonclinical samples.     

Use of health services for major depressive and anxiety disorders in Finland

Factors associated with people suffering from major depressive disorder (MDD) or anxiety disorders seeking or receiving treatment are not well known. In the Health 2000 Study, a representative sample (n=6005) of Finland's general adult (> or =30 years) population was interviewed with the M-CIDI for mental disorders and health service use for mental problems during the last 12 months. Predictors for service use among those with DSM-IV MDD (n=298) or anxiety disorders (n=242) were assessed. Of subjects with MDD, anxiety disorders, or both, 34%, 36%, and 59% used health services, respectively. Greater severity and perceived disability, psychiatric comorbidity, and living alone predicted health care use for MDD subjects, and greater perceived disability, psychiatric comorbidity, younger age, and parent's psychiatric problems for anxiety disorder subjects. The use of specialist-level mental health services was predicted by psychiatric comorbidity, but not characteristics of the disorders per se. Perceived disability and comorbidity are factors influencing the use of mental health services by both anxiety disorder and MDD subjects. However, still only approximately one-half of those suffering from even severe and comorbid disorders use health services for them.     

The reliability and validity of the korean version of the structured interview for prodromal syndrome

Objective

The Structured Interview for Prodromal Syndrome (SIPS) from Yale University is intended to diagnose prodromal syndrome of psychosis and to measure the severity of prodromal symptoms. Here, a Korean version of SIPS is presented, and its reliability, validity, and factor structures are examined using a representative Korean sample.

Methods

The Korean version of SIPS was administered to 40 participants over a period of 1 year. The inter-rater reliability and internal consistency of the SIPS were then evaluated. In addition, its factor structure was investigated using principal-axis factor analysis. Concurrent validity was explored using Pearson correlation coefficients with the Positive and Negative Syndrome Scale (PANSS).

Results

Of the 40 subjects, 12.5% developed psychotic disorders during the 1-year follow-up period. Inter-rater reliability was good (intra-class correlations=0.96), and internal consistency was acceptable (Cronbach''s alpha=0.83). A three-factor resolution displayed the best simple structure and accounted for 52.6% of all item variance. Factors 1 and 2 showed strong correlations with negative symptoms and cognitive dysfunction, respectively, on the PANSS. Factor 3 was not correlated with any factor on the PANSS.

Conclusion

The Korean version of SIPS is a reliable instrument for the assessment of prodromal symptoms in subjects and may be used to evaluate prodromal psychosis.