Reassessment of the psychometric characteristics and factor structure of the 'Perceived Stress Questionnaire' (PSQ): analysis in a sample of dental students.
BACKGROUND
The training to become a dentist can create psychological distress. The present study evaluates the structure of the 'Perceived Stress Questionnaire' (PSQ), its internal consistency model and interrelatedness with burnout, anxiety, depression and resilience among dental students.


METHODS
The study employed a cross-sectional design. A sample of Spanish dental students (n = 314) completed the PSQ, the 'Goldberg Anxiety and Depression Scale' (GADS), 'Connor-Davidson Resilience Scale' (10-item CD-RISC) and 'Maslach Burnout Inventory-Student Survey' (MBI-SS). The structure was estimated using Parallel Analysis from polychoric correlations. Unweighted Least Squares was the method for factor extraction, using the Item Response Theory to evaluate the discriminative power of items. Internal consistency was assessed by squaring the correlation between the latent true variable and the observed variable. The relationships between the PSQ and the other constructs were analysed using Spearman's coefficient.


RESULTS
The results showed a PSQ structure through two sub-factors ('frustration' and 'tenseness') with regard to one general factor ('perceived stress'). Items that did not satisfy discriminative capacity were rejected. The model fit were acceptable (GFI = 0.98; RSMR = 0.06; AGFI = 0.98; NFI = 0.98; RFI = 0.98). All the factors showed adequate internal consistency as measured by the congeneric model (≥0.91). High and significant associations were observed between perceived stress and burnout, anxiety, depression and resilience.


CONCLUSIONS
The PSQ showed a hierarchical bi-factor structure among Spanish dental students. Using the questionnaire as a uni-dimensional scale may be useful in perceived stress level discrimination, while the sub-factors could help us to refine perceived stress analysis and improve therapeutic processes.
Faculty of Health and Sport Sciences, University of Zaragoza, Zaragoza, Spain ; Primary Care Prevention and Health Promotion Research Network (RedIAPP), Zaragoza, Spain.
Jesús
J
Montero-Marin
Department of Preventive Medicine, Universidade Federal de São Paulo, São Paulo, Brasil.
Marcelo Marcos
MM
Piva Demarzo
Departament of Psychology, Instituto Superior da Maia, Castelo da Maia, Portugal.
Joao Paulo
JP
Pereira
Faculty of Health and Sport Sciences, University of Zaragoza, Zaragoza, Spain.
Marina
M
Olea
Miguel Servet University Hospital, Zaragoza, Spain ; Primary Care Prevention and Health Promotion Research Network (RedIAPP), Zaragoza, Spain.
Javier
J
García-Campayo
D000223:Adaptation, Psychological; D000328:Adult; D002055:Burnout, Professional; D003430:Cross-Sectional Studies; D003863:Depression; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D011594:Psychometrics; D055500:Resilience, Psychological; D013315:Stress, Psychological; D013335:Students, Dental / Q000523:psychology*; D011795:Surveys and Questionnaires; D055815:Young Adult