3.1 Participant characteristics

We present demographic characteristics of the total, PD and HC samples in Table 1. The participant characteristics of the testing and training dataset are available in the supplementary (Tables S1 and S2). The diagnostic information of the sample is presented in Table 2. The mean and standard deviations of all computed CAPE dimension scores of each sample group are presented in Table 3. Tables on the CAPE dimension scores of the testing and training dataset are available in the supplementary (Tables S3 and S4). The missing data of the total sample was minimal ranging from 88% (n = 1211) from the weighted severity positive symptoms score to 99% (n = 1374) from several variables such as frequency of positive symptoms, frequency of negative symptoms, and 10 other variables. Outliers were not removed because psychotic symptoms scores vary greatly in the field and this should be reflected in our data.

TABLE 1. Participants' characteristics Characteristic Total sample (N = 1375) Individuals with a psychotic disorder (n = 868) Healthy individuals (n = 507) n/M %/SD n/M %/SD n/M %/SD Age (M, SD) 28.67 9.03 27.98 7.99 29.87 10.48 Sex (n, %) Male 900 65.45% 655 75.46% 245 48.32% Female 475 34.55% 213 24.54% 262 51.68% Highest educational degree (n, %) No education (0) 7 0.51% 7 0.81% 0 0.00% Primary school (1) 114 8.29% 101 11.64% 13 2.56% Secondary school (2–3) 343 24.95% 264 30.41% 79 15.58% High school (4–5) 381 27.71% 220 25.35% 161 31.76% Vocational education (6–7) 429 31.20% 231 26.61% 198 39.05% University 89 6.47% 34 3.92% 55 10.85% Marital status (n, %) Not married 1028 74.76% 741 85.37% 287 56.61% Married/living together 265 19.27% 80 9.22% 185 36.49% Divorced/Widowhood 40 2.91% 26 3.00% 14 2.76% Note: Secondary school consists of the following Dutch system of secondary school, LBO/HH/LHNO/VBO and MAVO/VMBO; high school consists of HAVO and VWO; vocational education consists of MBO and HBO. The PD sample was younger than the HC sample (t[850.83] = 3.51, p < 0.001), had fewer females (χ2[1, N = 1375] = 103.04, p < 0.001), had lower education level (χ2[8, N = 1375] = 151.93, p < 0.001), and fewer were married (χ2[3, N = 1375] = 161.52, p < 0.001). TABLE 2. Diagnostic information of the total sample (N = 1375) Characteristic Diagnostic code DSM-IV-TR Individuals with a psychotic disorder (n = 868) Healthy individuals (n = 507) n % n % Schizophrenia, disorganized type 295.1 35 4.03% 0 0% Schizophrenia, catatonia type 295.2 1 0.12% 0 0% Schizophrenia, paranoid type 295.3 487 56.11% 0 0% Schizophreniform disorder 295.4 43 4.95% 0 0% Schizophrenia, residual type 295.6 19 2.19% 0 0% Schizoaffective disorder 295.7 102 11.75% 0 0% Schizophrenia, undifferentiated type 295.9 52 5.99% 0 0% Delusional disorder 297.1 17 1.96% 0 0% Brief psychotic disorder 298.8 23 2.65% 0 0% Psychotic disorder NOS 298.9 89 10.25% 0 0% Diagnosis deferred 799.9 0 0.00% 3 0.59% Bereavement V62.82 0 0.00% 1 0.20% No diagnosis V71.09 0 0.00% 503 99.21% Abbreviation: NOS, not otherwise specified. TABLE 3. Means and standard deviations of the CAPE dimension scores Measure Total sample (N = 1375) Individuals with a psychotic disorder (n = 868) Healthy individuals (n = 507) n M SD n M SD n M SD Possible score range Three dimensions F.POS 1374 1.50 0.47 867 1.68 0.50 507 1.19 0.17 1–4 F.NEG 1374 1.82 0.54 867 2.02 0.53 507 1.47 0.32 1–4 F.DEP 1374 1.84 0.54 867 2.00 0.58 507 1.56 0.33 1–4 D.POS 1374 1.43 0.52 867 1.64 0.55 507 1.07 0.12 1–4 D.NEG 1373 1.69 0.61 866 1.91 0.62 507 1.32 0.34 1–4 D.DEP 1371 1.85 0.70 864 2.06 0.72 507 1.49 0.48 1–4 Nine-cluster F.BIZ 1374 1.40 0.52 867 1.58 0.56 507 1.07 0.16 1–4 F.HAL 1369 1.30 0.49 864 1.47 0.55 505 1.02 0.09 1–4 F.PAR 1374 1.66 0.57 867 1.84 0.61 507 1.35 0.30 1–4 F.MAG 1373 1.74 0.81 866 1.92 0.86 507 1.43 0.59 1–4 F.GRA 1371 1.61 0.75 864 1.79 0.82 507 1.30 0.48 1–4 F.SOW 1373 1.91 0.62 866 2.12 0.62 507 1.57 0.43 1–4 F.AFF 1373 1.73 0.72 866 1.98 0.74 507 1.30 0.43 1–4 F.AVO 1373 1.80 0.55 866 1.99 0.57 507 1.49 0.33 1–4 D.BIZ 1374 1.40 0.59 867 1.61 0.65 507 1.03 0.11 1–4 D.HAL 1367 1.32 0.56 862 1.51 0.64 505 1.01 0.06 1–4 D.PAR 1373 1.62 0.69 866 1.87 0.74 507 1.20 0.28 1–4 D.MAG 1368 1.34 0.66 862 1.52 0.77 506 1.04 0.18 1–4 D.GRA 1364 1.34 0.71 857 1.52 0.84 507 1.06 0.22 1–4 D.SOW 1369 1.66 0.67 862 1.88 0.69 507 1.28 0.41 1–4 D.AFF 1370 1.63 0.76 863 1.87 0.81 507 1.22 0.41 1–4 D.AVO 1370 1.74 0.65 863 1.95 0.67 507 1.38 0.40 1–4 Mossaheb et al. (2012) DF.POS 1374 1.46 0.48 867 1.66 0.50 507 1.13 0.14 1–8 DF.NEG 1374 1.76 0.55 867 1.97 0.55 507 1.39 0.31 1–8 DF.DEP 1374 1.84 0.60 867 2.03 0.62 507 1.52 0.39 1–8 3 items 1374 1.50 0.67 867 1.77 0.71 507 1.05 0.15 1–4 Jaya et al. (2018) SEV.POS 1211 2.57 1.96 742 3.35 2.14 469 1.34 0.40 1–16 Note: Presented scores are average scores (i.e., the mean of item scores). Abbreviations: AFF, affective flattening (3 items); AVO, avolition (7 items); BIZ, bizarre experiences dimension (7 items); CAPE, community assessment of psychic experiences; D, distress scale; DEP, depression dimension (8 items); DF, sum of frequency and distress scale following Mossaheb et al. (2012); F, frequency scale; GRA, grandiosity dimension (2 items); HAL, hallucinations dimension (4 items); MAG, magical thinking dimension (2 items); NEG, negative symptoms dimension (14 items); PAR, paranoia (5 items); POS, positive symptoms dimension (20 items); SSEV.POS, severity positive symptom dimension scale is computed by multiplying (weighting) each frequency answer with its corresponding distress score following Jaya et al. (2018)OW, social withdrawal dimension (4 items); Three items, sum of frequency and distress scale of Q7, Q31, and Q33 recommended in Mossaheb et al. (2012).

The average age of the total sample was 28.7 years (SD = 9.0), ranging from 15 to 61 years and 65% were male. The PD sample was younger than the HC sample (t (850.83) = 3.51, p < 0.001), had fewer females (χ2 [1, N = 1375] = 103.04, p < 0.001), had lower education level (χ2 [8, N = 1375] = 151.93, p < 0.001), and fewer were married (χ2 [3, N = 1375] = 161.52, p < 0.001).

3.2 Reliability and factorial structure of the CAPE

In the total dataset, the three-dimensional factorial structure met the fit criteria for RMSEA and SRMR, but not CFI (χ[816] = 3263.278, p < 0.001, CFI = 0.857, RMSEA = 0.057 [90% CI 0.055, 0.059], SRMR = 0.052, AIC = 108,576). The Omega reliability estimates of the three-dimensional factorial structure were good (positive symptom dimension, ω = 0.92; negative symptom dimension, ω = 0.91; depressive symptom dimension, ω = 0.87). Similarly, the nine-cluster factorial structure met the fit criteria for RMSEA and SRMR, but not CFI (χ[808] = 2171.591, p < 0.001, CFI = 0.921, RMSEA = 0.043 [90% CI 0.041, 0.045], SRMR = 0.053, AIC = 106,932). The Omega reliability estimates of the nine-cluster factorial structure were acceptable (positive symptom dimension, ω = 0.88; bizarre experiences subdimension, ω = 0.85, hallucinations subdimension, ω = 0.81, grandiosity subdimension, ω = 0.81, magical thinking subdimension, ω = 0.65, paranoia subdimension, ω = 0.79; negative symptom dimension, ω = 0.92; affective flattening subdimension, ω = 0.82, avolition subdimension, ω = 0.83, social withdrawal subdimension, ω = 0.78; depressive symptom dimension, ω = 0.88).

A similar pattern of results was found in the training and testing dataset. In the training dataset the three-dimensional (χ[816] = 2278.401, p < 0.001, CFI = 0.860, RMSEA = 0.058 [90% CI 0.056, 0.061], SRMR = 0.058, AIC = 62,455) and nine-cluster factorial structure (χ[808] = 1617.551, p < 0.001, CFI = 0.923, RMSEA = 0.043 [90% CI 0.040, 0.047], SRMR = 0.058, AIC = 61,424) met the fit criteria for RMSEA and SRMR, but not CFI. The Omega reliability estimates of the three-dimensional factorial structure were good (positive symptom dimension, ω = 0.92; negative symptom dimension, ω = 0.91; depressive symptom dimension, ω = 0.88), and likewise for the nine-cluster factorial structure (positive symptom dimension, ω = 0.89; bizarre experiences subdimension, ω = 0.86, hallucinations subdimension, ω = 0.81, grandiosity subdimension, ω = 0.82, magical thinking subdimension, ω = 0.69, paranoia subdimension, ω = 0.78; negative symptom dimension, ω = 0.93; affective flattening subdimension, ω = 0.85, avolition subdimension, ω = 0.84, social withdrawal subdimension, ω = 0.79; depressive symptom dimension, ω = 0.89).

Again, in the testing dataset, both factorial structures met the fit criteria for RMSEA and SRMR, but not CFI (three-dimensional, χ[816] = 1583.627, p < 0.001, CFI = 0.840, RMSEA = 0.059 [90% CI 0.054, 0.063], SRMR = 0.059, AIC = 32,638; nine-cluster, χ[808] = 1205.801, p < 0.001, CFI = 0.918, RMSEA = 0.042 [90% CI 0.037, 0.047], SRMR = 0.062, AIC = 32,076). The Omega reliability estimates in the testing dataset were similar to those in the training dataset (three-dimensional: positive symptom dimension, ω = 0.91; negative symptom dimension, ω = 0.90; depressive symptom dimension, ω = 0.86; nine-cluster: positive symptom dimension, ω = 0.87; bizarre experiences subdimension, ω = 0.83, hallucinations subdimension, ω = 0.82, grandiosity subdimension, ω = 0.80, magical thinking subdimension, ω = 0.54, paranoia subdimension, ω = 0.80; negative symptom dimension, ω = 0.92; affective flattening subdimension, ω = 0.82, avolition subdimension, ω = 0.82, social withdrawal subdimension, ω = 0.78; depressive symptom dimension, ω = 0.87).

3.3 The cut-off scores of the CAPE

The ROC analyses on the cut-off scores of the 27 dimensional scores from the total dataset (N = 1375) are presented in Table 4, and a similar table from the training (n = 917) and testing (n = 458) dataset are presented in Tables S5 and