The duration of untreated psychosis has been largely associated with poor outcomes in psychosis. Actual diagnostic tools may be used by very specialized teams and need sustained evaluation. We present a French version of a self-report questionnaire: the 16-item Prodromal Questionnaire (fPQ16). Our objective was to evaluate its predictive value for an ultra-high-risk state (UHR) or psychosis. The population enrolled was consulting in a young adults and adolescents center in Sainte-Anne hospital, Paris, France.
PQ16 had first been translated into French and independently back translated and validated by the original authors. Between November 2016 and May 2018, every C'JAAD consulting patient was proposed to fill in the fPQ16. Each patient was next evaluated with the French version of the comprehensive assessment of at-risk mental state (CAARMS), which detects UHR or psychosis. Statistical analysis of fPQ16 concurrent validity was performed using ROC curves. fPQ16 acceptability was studied by four additional questions especially designed for that purpose.
One hundred participants were included. Mean age was 19.85years (SD 3.3 y). Fifty-eight percent of patients included were diagnosed with UHR (40%) or psychotic (18%) state after CAARMS evaluation. Mean score at fPQ16 was 5.7 (SD 3.8). Best cut-off score was 4 positive items, with excellent sensibility (91%) and correct specificity (60%). Positive predictive value of fPQ16 was 76%. Area under the curve was 0.85 (P<0.0001). fPQ16 showed good acceptability.
fPQ16 had good screening performances in our population. Cut-off score was lower than in previous studies, but performances were equal or better. As a well-accepted and short questionnaire, the fPQ16 could be a great screening tool in primary care. A version with 18-items, including two items focused on thought content and disorganization that are missing in PQ16, is under evaluation.