The Italian version of the 16-item Prodromal Questionnaire (PQ-16) and its psychometric features in help-seeking ultra-high-risk subjects and in the general population.

BACKGROUND: Increasing attention to the early stages of psychosis and the identification of symptomatic prodromal states have led to the development of a growing number of screening tools. The 16-item version of the Prodromal Questionnaire (PQ-16) is a worldwide used self-administered tool for this purpose. However, to date, fundamental psychometric properties of PQ-16 were not thoroughly investigated. This study aimed to examine the structural validity, measurement invariance, reliability and other psychometrical properties of the Italian version of the PQ-16 (iPQ-16) in help-seeking individuals and in the general population. METHODS: The iPQ-16 was administered to 449 young outpatients attending six community mental health services and to 318 control participants enrolled in educational environment. Confirmatory factor analyses (CFAs), measurement invariance (MI) between the help-seeking group and the general population sample, convergent validity, test-retest reliability, internal consistency, and prevalence analyses were performed. Lastly, the validity of the adopted PQ-16 cut-offs through Receiver Operating Characteristic (ROC) curves plotted against CAARMS diagnoses was also tested. RESULTS: CFAs confirmed the single-factor structure for the iPQ-16 and scalar MI was reached. The iPQ-16 showed high internal consistency, test-retest reliability, convergent validity, and acceptable diagnostic accuracy. ROC analysis suggested a score of ≥4 as best cut-off. CONCLUSIONS: The iPQ-16 represents a valid and reliable questionnaire for the assessment of high mental risk in both Italian outpatients and general student population. It has good psychometric properties and is easy to implement as UHR screening for clinical as well as research purposes.

Improving screening methods for psychosis in an adolescent help-seeking population using the Child Behavior Checklist (CBCL) and the Youth Self Report (YSR) versus the Prodromal Questionnaire -16 items version (PQ-16).

BACKGROUND: Screening methods for detecting Ultra High Risk status (UHR) or psychosis should be improved, especially in adolescent samples. We therefore tested whether the Child Behavior Checklist (CBCL) and the Youth Self Report (YSR) add value to the Prodromal Questionnaire-16 items version (PQ-16) for detecting UHR status or psychosis. METHODS: We included help-seeking adolescents who had completed the PQ-16, YSR, CBCL, and a Comprehensive Assessment of an At Risk Mental States (CAARMS) interview, and used independent samples t-tests and binary logistic regression analyses to determine the scales contributing to the prediction of UHR status or of having reached the psychosis threshold (PT). Cutoff scores were determined using ROC analyses. RESULTS: Our sample comprised 270 help-seeking adolescents (mean age 14.67; SD 1.56, range 12-17); 67.8% were girls and 66.3% were of Dutch origin. The Thought Problems syndrome scales of both the YSR and the CBCL best predicted UHR or PT, and had screening values comparable to the PQ-16. Other syndrome scales did not improve screening values. Although combining measures reduced the number of false negatives, it also increased the number of adolescents to be interviewed. The best choice was to combine the YSR Thought Problems scale and the PQ-16 as a first-step screener. CONCLUSIONS: Combining measures improves the detection of UHR or PT in help-seeking adolescents. The Thought Problems subscales of the YSR and CBCL can both be used as a first-step screener in the detection of UHR and/or psychosis. Trial registration Permission was asked according to the rules of the Ethics Committee at Leiden. This study is registered as NL.44180.058.13.

Assessment of Psychotic Symptoms in Individuals Exposed to Very High or Extreme Altitude: A Field Study.

Hüfner, Katharina, Fabio Caramazza, Agnieszka E. Stawinoga, Evelyn R. Pircher Nöckler, Paolo Fusar-Poli, Sanjeeb S. Bhandari, Buddha Basnyat, Monika Brodmann Maeder, Giacomo Strapazzon, Iztok Tomazin, Barbara Sperner-Unterweger, and Hermann Brugger. Assessment of psychotic symptoms in individuals exposed to very high or extreme altitude: A field study. High Alt Med Biol. 22:369-378, 2021. Background: Symptoms of psychosis such as hallucinations can occur at high or extreme altitude and have been linked to accidents on the mountain. No data are available on how to assess such symptoms in the field and what their prevalence or predisposing factors might be. Methods: In this field study at Everest Base Camp (5,365 m) in Nepal, 99 participants of organized expeditions underwent 279 assessments: The High Altitude Psychosis Questionnaire (HAPSY-Q), the Prodromal Questionnaire, 16-items (PQ-16), and the Mini International Neuropsychiatric Interview (M.I.N.I., psychosis section) were collected together with further clinical data. Statistical analysis was done for each phase, that is, altitude range of the climb, and overall data. Results: One of 97 climbers fulfilled the M.I.N.I. diagnostic criteria for psychosis during one acclimatization climb. At least one endorsed item on the HAPSY-Q and the PQ-16, indicating the presence of symptoms of psychosis in the absence of a psychotic disorders, were identified in 10/97 (10.3%) and 18/87 (20.7%) participants respectively. The scores of the HAPSY-Q and the PQ-16 were correlated (r = 0.268, p < 0.001). Odds ratio analysis identified an increased risk for accidents in individuals with endorsed items on the HAPSY-Q. Conclusions: The diagnosis of high altitude psychosis is rare in climbers during organized expeditions. Nevertheless, subdiagnostic symptoms of psychosis occurred in a significant proportion of climbers. Future research is needed to validate these pilot findings.

Screening for psychosis risk among help-seeking adolescents: Application of the Italian version of the 16-item prodromal questionnaire (iPQ-16) in child and adolescent neuropsychiatry services.

AIM: The 16-item Prodromal Questionnaire (PQ-16) is a versatile screen tool for routine screening of at-risk individuals. We wished to evaluate the psychometric properties of the Italian version of the PQ-16 (iPQ-16) in a sample of 72 help-seeking adolescents (age range 13-17 years) referred to child and adolescent neuropsychiatry services for diagnostic assessment. METHODS: Participants who completed iPQ-16 were subsequently interviewed with the Comprehensive Assessment of At-Risk Mental States (CAARMS) to confirm the psychosis high risk state. We then examined the diagnostic accuracy (sensitivity, specificity, positive and negative predictive values [PPV e NPV]) and concurrent validity between iPQ-16 and CAARMS using Cronbach's alpha and Cohen's kappa. We also tested the validity of the adopted iPQ-16 cut-offs through Receiver Operating Characteristic (ROC) curves plotted against CAARMS diagnoses and the 1-year predictive validity of the iPQ-16. RESULTS: Overall, the psychometric properties of the iPQ-16 were satisfactory. The iPQ-16 showed high internal consistency (Cronbach's alpha = .827) and acceptable diagnostic accuracy (77% sensitivity, 72% PPV) and concurrent validity (Cohen's k = 0.309). ROC analyses pointed to iPQ-16 total distress score of ≥10 as best cut-off. CONCLUSION: The iPQ-16 is a reliable and valid instrument for routine screening of at-risk individuals in Italian neuropsychiatry services.

Validation of the Korean version of the 16-Item Prodromal Questionnaire in a Non-Help-Seeking College Population.

OBJECTIVE: To examine the reliability and validity of the Korean version of the 16-item Prodromal Questionnaire (KPQ-16) in non-help-seeking university students. METHODS: Among 2,246 university students participated in the initial screening, 257 subjects with KPQ-16 scores ≥4 were interviewed. The criteria for ultra-high risk (UHR) of psychosis of the Comprehensive Assessment of At-Risk Mental States (CAARMS) were the gold standard for diagnosis. An exploratory modified version of the questionnaire (mKPQ-16), to which three items from the Eppendorf Schizophrenia Inventory were added, was also used to compensate for items on thought and cognitive problems. RESULTS: Seventeen subjects met the CAARMS criteria for UHR of psychosis. The area under the receiver operating characteristic curve (AUROC) was highest for the mKPQ-16 total score (AUROC=0.831, p<0.001). The use of cutoff total scores of 7 for the mKPQ-16 and 6 for the KPQ-16 resulted in the best balance of sensitivity (76.5% and 64.7%, respectively) and specificity (75.4% and 71.2%, respectively). CONCLUSION: The Korean versions of the PQ-16 are good instruments for screening for psychosis risk in university students. This validation of a questionnaire version with a small number of items may make it feasible to screen large numbers of young adults in the community.