A peer-reviewed, evidence-based journal for clinicians in the field of neuroscience
Issue link: https://innovationscns.epubxp.com/i/555782
Innovations in CLINICAL NEUROSCIENCE [ V O L U M E 1 2 , N U M B E R 7 – 8 , J U L Y – A U G U S T 2 0 1 5 ] 24 Data shown in Table 3 suggest that the CD-Quest was able to identify different groups, indicating that subjects with depressive symptoms had a mean score significantly higher than those not presenting depressive symptoms. Table 4 also shows that the CD-Quest mean score was significantly higher in anxious subjects (BAI≥11) than in nonanxious subjects (BAI<11). Principal component analysis (PCA). The Kaiser-Meyer-Olkin (KMO) measure was 0.86, and the Bartlett's sphericity test was highly significant (chi-squared=749,22; p<0.001), which suggests that the sample is adequate to perform the principal component analysis. The factor structure that best explained the variance of the CD- Quest items was unidimensional (i.e., all of the items were loaded onto one single component). This conclusion was based upon comparison of different techniques: K aiser's criterion (number of factors equal to number of eigenvalues >1), parallel analysis, and the distribution of factor loadings across different components. The explained variance for one single dimension was 29 percent, which is expected for a unidimensional measure with 15 items. In order to maximize the variance of the squared loadings on all the items, the varimax rotation was performed along with the PCA. Table 5 shows the rotated component matrix with loadings of the CD-Quest items (total scale), their respective communalities, and their corrected item-total correlations. Confirmatory factor analysis. A confirmatory factor analysis was performed in order to check the unidimensionality of the CD-Quest. The fit measures for the overall model are close to the expected (RMSEA<0.075, CFI=0.87, GFI=0.89, and chi-squared (90)=179,85, p<0.001) in the literature 30 and all the regression coefficients are 0.40 or greater. Figure 2 shows the structural equation modeling with the regression coefficients for the 15 items of the CD-Quest. Test-retest reliability. Intraclass correlation (ICC) was calculated to investigate the test- retest reliability for the CD-Quest over a period of 3 to 4-weeks. The results of the ICC for the total scale (ICC=0.87+0.82–0.90 confidence interval [CI]), and for the frequency and intensity subscales (0.86+0.81–0.89 CI and 0.85+0.80–0.89 CI, respectively), indicated very satisfactory repeatability. DISCUSSION The aim of this study was to develop and validate the CD-Quest, a questionnaire designed to allow clinicians and researchers to assess commonly identified cognitive distortions in CBT clinical practice. TABLE 2. CD-Quest concurrent validity in a sample of university students (N=184) CD-QUEST BAI BDI SS FREQUENCY SS INTENSITY Total scale 0.52** 0.65** 0.95** 0.96** SS frequency 0.50** 0.61** NA 0.85** S S intensity 0.47** 0.59** 0.85** NA ** p< 0.01 SS: subscale (CD-Quest); BAI: Beck Anxiety Inventory; BDI: Beck Depression Inventory; NA: not applicable TABLE 3. Classification of CD-Quest scores according to magnitude (severity) of distortions in a sample of university students (N=184) PERCENTILE CD-QUEST SCORES CLASSIFICATION 1 3 Absent/Minimal 5 4 10 8 15 10 20 11 25 14 30 15 Slightly 40 18 50 22 60 25 Moderately 70 29 75 32 80 35 Severely 85 37 90 39 95 42 99 52 100 60