Polish adaptation of the Prodromal Questionnaire-Brief version PQ-B(PL) in psychiatric patients and healthy persons

Aim. Cognitive and affective experiences considered typical of psychotic disorders may also occur in the general population, though in a less severe form. The ability to differentiate them from prodromal states, preceding the onset of full-blown psychosis, is an important element of prevention and early detection of high risk of a sudden deterioration of mental state. In response to the current lack of questionnaire tools enabling assessment of psychotic-like experiences (PLEs), an attempt was made to adapt the PQ-B questionnaire for use in the Polish population. Method. In the pilot study, a sample of 652 persons (66% women), aged 18-78 years, approximately 10% of whom were psychiatric patients, completed the Polish version of the PQ-B, and the O-LIFE, HCL-33, SWLS and TCT-DP measures. Results. Results yielded a one-factor structure, satisfactory reliability (alpha > 0.85) and construct validity of the 21-item self-report questionnaire assessing the incidence of PLEs in the past month and severity of accompanying distress. Furthermore, there were significant correlations between PQ-B scores and symptoms of schizotypy (especially unusual perceptual experiences and cognitive disorganization), emotional lability (p < 0.05) and depressed mood (p > 0.001) typical of hypomania, as well as unconventional thinking (p > 0.05). Conclusions. The PQ-B(PL) can be a useful tool in both Polish clinical practice and scientific research, filling the existing gap among screening tests for traits on the border of health and psychopathology.