The Validity of the 16-Item Version of the Prodromal Questionnaire (PQ-16) to Screen for Ultra High Risk of Developing Psychosis in the General Help-Seeking Population

Ising, Helga K.; Veling, Wim; Loewy, Rachel; Rietveld, Marleen W.; Rietdijk, Judith; Dragt, Sara; Klaassen, Rianne; Nieman, Dorien H.; Wunderink, Lex; Linszen, Don; Gaag, Mark van der

doi:10.1093/schbul/sbs068

Cited by 338 publications

(411 citation statements)

References 26 publications

Supporting

Mentioning

384

Contrasting

Order By: Relevance

“…In the present study, item distress assessment also appears to be more effective than total number of symptoms endorsed in identifying the most promising cut-off. Moreover, our finding that distress scores, as opposed to symptom total scores, are more accurate in preselecting UHR/FEP individuals is consistent with much of the current literature [11,33,35] and is significant given current guidelines on early detection of psychoses [36].…”

Section: Concurrent Validity and Diagnostic Accuracy Measuressupporting

confidence: 85%

The Italian Version of the Brief 21-Item Prodromal Questionnaire: Field Test, Psychometric Properties and Age-Sensitive Cut-Offs

et al. 2018

View full text Add to dashboard Cite

Background: The Brief, 21-item version of the Prodromal Questionnaire (PQ-B) is a promising screener for psychosis-risk states that could be implemented in routine clinical practice. In this study, we assessed psychometric properties of the Italian version of the PQ-B (iPQ-B) in a sample of 243 help-seekers, aged 13–35 years. Sampling and Methods: After completing the iPQ-B, participants were assessed with the Comprehensive Assessment of At-Risk Mental States (CAARMS). Diagnostic accuracy (sensitivity, specificity, positive and negative predictive values [PPV and NPV], positive and negative likelihood ratios) and concurrent validity between PQ-B and CAARMS were determined using Cronbach’s alpha and Cohen’s kappa. We also tested the validity of the adopted PQ-B cut-offs through Receiver Operating Characteristic (ROC) curves plotted against CAARMS diagnoses and the predictive validity of the iPQ-B at 1-year follow-up. Results: The iPQ-B showed high internal consistency (Cronbach’s alpha = 0.868), acceptable diagnostic accuracy and concurrent validity (70% sensitivity, 67% specificity, 81% PPV, Cohen’s kappa = 0.335). ROC analyses pointed to threshold of ≥20 on the PQ-B total distress score as best cut-off. After 12 months of follow-up, 11% of participants who scored ≥4 on the PQ-B distressing item total score and did not meet CAARMS psychosis criteria at baseline, developed a psychotic disorder. Interestingly, age had significant negative correlations with iPQ-B scores and adolescents (aged < 18 years) showed higher iPQ-B scores than young adults. Conclusions: Overall, the psychometric properties of the iPQ-B were satisfactory. As iPQ-B scores appeared inversely associated to age, age-tailored cut-off scores are recommended for screening purposes in child-adolescent cohorts.

show abstract

Section: Concurrent Validity and Diagnostic Accuracy Measuressupporting

confidence: 85%

The Italian Version of the Brief 21-Item Prodromal Questionnaire: Field Test, Psychometric Properties and Age-Sensitive Cut-Offs

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Yet, at correct classification rates of 70.7 and 64.8% when the compound rating was considered, both the PDI and LSHS-R were superior to the 44% rate recently reported for the Prodromal Questionnaire in a large, more unselected help-seeking sample [37]. …”

Section: Discussionmentioning

confidence: 92%

“…Consequently, had they been used as a screener as suggested by several studies [36,37,38], simple-rated PLEs would have been highly sensitive but far too unspecific, as they would have detected nearly everyone with mental problems presenting at the early detection center, including those without any mental disorder. The specificity of PLEs might have been higher at higher thresholds, but most likely at the cost of sensitivity, as reported in a study evaluating the CAPE as a screening instrument for at-risk states according to the Comprehensive Assessment of At-Risk Mental States [36].…”

Section: Discussionmentioning

confidence: 99%

Self-Reported Psychotic-Like Experiences Are a Poor Estimate of Clinician-Rated Attenuated and Frank Delusions and Hallucinations

et al. 2013

View full text Add to dashboard Cite

Background: One reason for the decision to delay the introduction of an Attenuated Psychosis Syndrome in the main text of the fifth edition of the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders was the concern that attenuated psychotic symptoms (APS) might in fact be common features in adolescents and young adults from the general population of no psychopathological significance in themselves. This concern was based on reports of high prevalence rates of psychotic-like experiences (PLEs) in the general population and the assumption that PLEs are a good estimate of APS. Although the criterion validity of self-reported PLEs had already been studied with respect to clinician-rated psychotic symptoms and found insufficient, it had been argued that PLEs might in fact be more comparable with mild, subclinical expressions of psychotic symptoms and, therefore, with APS. The present paper is the first to specifically study this assumption. Sampling and Methods: The sample consisted of 123 persons seeking help at a service for the early detection of psychosis, of whom 54 had an at-risk mental state or psychosis, 55 had a nonpsychotic mental disorder and 14 had no full-blown mental disorder. PLEs were assessed with the Peters Delusion Inventory and the revised Launay-Slade Hallucination Scale, and psychotic symptoms and APS were assessed with the Structured Interview for Prodromal Syndromes. Results: At a level of agreement between the presence of any PLE (in 98.4% of patients) and any APS (in 40.7%) just exceeding chance (κ = 0.022), the criterion validity of PLEs for APS was insufficient. Even if additional qualifiers (high agreement or distress, preoccupation and conviction) were considered, PLEs (in 52.8%) still tended to significantly overestimate APS, and agreement was only fair (κ = 0.340). Furthermore, the group effect on PLE prevalence was, at most, moderate (Cramer's V = 0.382). Conclusions: The prevalence of APS cannot be deduced from studies of PLEs. Thus, the high population prevalence rate of PLEs does not allow the conclusion that APS are common features of no pathological significance and would lack clinical validity as an Attenuated Psychosis Syndrome in the Diagnostic and Statistical Manual of Mental Disorders, 5th edition. Rather, the population prevalence rate of APS has to be assumed to be largely unknown at present but is likely lower than indicated by epidemiological studies of PLEs. Therefore, dedicated studies are warranted, in which APS are assessed in a way that equates to their clinical evaluation.

show abstract

“…The Prodromal Questionnaire 16 37 is an online screener used to preselect patients for the CAARMS interview in the mental health care and takes 2 min time. The costs of identifying the UHR patients and training staff (US$724) were not factored into the cost of intervention, because they are the same for both groups.…”

Section: Costs Of Identifying Uhr Patientsmentioning

confidence: 99%

Four-Year Cost-effectiveness of Cognitive Behavior Therapy for Preventing First-episode Psychosis: The Dutch Early Detection Intervention Evaluation (EDIE-NL) Trial

Ising

Lokkerbol

Rietdijk

et al. 2016

SCHBUL

View full text Add to dashboard Cite

Background . This study aims to evaluate the long-term costeffectiveness of add-on cognitive behavior therapy (CBT) for the prevention of psychosis for individuals at ultrahigh risk (UHR) of psychosis. Method. The Dutch Early Detection and Intervention randomized controlled trial was used, comparing routine care (RC; n = 101) with routine care plus CBT for UHR (here called CBTuhr; n = 95). A cost-effectiveness analysis was conducted with treatment response (defined as proportion of averted transitions to psychosis) as an outcome and a cost-utility analysis with quality-adjusted life years (QALYs) gained as a secondary outcome. Results. The proportion of averted transitions to psychosis was significantly higher in the CBTuhr condition (with a risk difference of 0.122; b = 1.324, SE b = 0.017, z = 7.99, P < 0.001). CBTuhr showed an 83% probability of being more effective and less costly than RC by −US$ 5777 (savings) per participant. In addition, over the 4-year follow-up period, cumulative QALY health gains were marginally (but not significantly) higher in CBTuhr than for RC (2.63 vs. 2.46) and the CBTuhr intervention had a 75% probability of being the superior treatment (more QALY gains at lower costs) and a 92% probability of being costeffective compared with RC at the Dutch threshold value (US$ 24 560; €20 000 per QALY). Conclusions. Add-on preventive CBTuhr had a high likelihood (83%) of resulting in more averted transitions to psychosis and lower costs as compared with RC. In addition, the intervention had a high likelihood (75%) of resulting in more QALY gains and lower costs as compared to RC.

show abstract

The Validity of the 16-Item Version of the Prodromal Questionnaire (PQ-16) to Screen for Ultra High Risk of Developing Psychosis in the General Help-Seeking Population

Cited by 338 publications

References 26 publications

The Italian Version of the Brief 21-Item Prodromal Questionnaire: Field Test, Psychometric Properties and Age-Sensitive Cut-Offs

The Italian Version of the Brief 21-Item Prodromal Questionnaire: Field Test, Psychometric Properties and Age-Sensitive Cut-Offs

Self-Reported Psychotic-Like Experiences Are a Poor Estimate of Clinician-Rated Attenuated and Frank Delusions and Hallucinations

Four-Year Cost-effectiveness of Cognitive Behavior Therapy for Preventing First-episode Psychosis: The Dutch Early Detection Intervention Evaluation (EDIE-NL) Trial

Contact Info

Product

Resources

About