Table 1.
Demographic data, cognitive functions and P300 parameters
| H | ARMS | Sch | Effect Size | Group Comparison | |
|---|---|---|---|---|---|
| (n = 28) | (n = 33) | (n = 39) | |||
| Male/female | 16/12 | 23/10 | 16/23 | - | χ2 = 6.00, p = 0.05, n.s. |
| Age (years) | 21.7 (5.0) | 19.2 (4.6) | 24.4 (7.2) | - | F(2,97) = 7.93, p = 0.001 **, ARMS < Sch |
| Age of onset (years) | - | - | 24.4 (6.6) | - | - |
| Duration of illness (years) | - | - | 2.7 (3.0) | - | - |
| JART a | 102.5 (7.4) | 96.9 (10.0) | 99.3 (11.1) | - | F(2,85) = 1.91, p = 0.15, n.s. |
| PANSS: positive symptom | - | 13.1 (3.7) | 16.7 (5.8) | - | p = 0.003 **, ARMS < Sch |
| negative symptom | - | 19.5 (7.2) | 19.1 (7.4) | - | p = 0.81, n.s. |
| general psychopathology | - | 34.9 (8.9) | 36.5 (9.1) | - | p = 0.45, n.s. |
| mGAF | - | 46.5 (9.1) | 34.1 (8.6) | - | p < 0.001 **, ARMS > Sch |
| SCoRS | - | 4.7 (2.2) | 5.8 (2.3) | - | p = 0.069, n.s. |
| BACS a,b: verbal memory | −0.16 (1.1) | −0.54 (1.4) | −1.46 (1.6) | 0.12 | F(2,86) = 5.81, p = 0.004 **, H, ARMS > Sch |
| working memory | 0.10 (0.8) | −0.9 (1.3) | −1.32 (1.3) | 0.15 | F(2,86) = 7.99, p = 0.001 **, H > ARMS, Sch |
| motor function | −0.15 (1.0) | −1.31 (1.7) | −2.04 (1.5) | 0.18 | F(2,86) = 9.45, p < 0.001 **, H > ARMS, Sch |
| verbal fluency | 0.096 (1.0) | −0.96 (1.2) | −1.44 (1.3) | 0.19 | F(2,86) = 9.84, p < 0.001 **, H > ARMS, Sch |
| attention | 0.70 (0.8) | −0.22 (1.5) | −1.60 (1.3) | 0.32 | F(2,86) = 20.97, p < 0.001 **, H > ARMS > Sch |
| executive function | 0.29 (1.1) | −0.36 (1.3) | −1.47 (1.9) | 0.16 | F(2,86) = 8.64, p < 0.001 **, H, ARMS > Sch |
| composite score c | 0.14 (0.5) | −0.72 (1.0) | −1.55 (1.2) | 0.28 | F(2,86) = 17.52, p < 0.001 **, H > ARMS > Sch |
| P300 Amplitude (µV):T3 | 9.26 (4.5) | 6.12 (3.1) | 5.14 (2.6) | 0.20 | F(2,97) = 11.76, p < 0.001 **, H > ARMS, Sch |
| T4 | 9.30 (5.5) | 6.50 (4.1) | 4.04 (3.0) | 0.20 | F(2.97) = 12.19, p < 0.001 **, H > ARMS, Sch |
| Fz | 13.59 (7.2) | 8.46 (6.3) | 4.80 (4.2) | 0.27 | F(2,97) = 17.89, p < 0.001 **, H > ARMS > Sch |
| Cz | 19.51 (8.6) | 13.08 (6.3) | 7.07 (3.6) | 0.40 | F(2,97) = 32.33, p < 0.001 **, H > ARMS > Sch |
| Pz | 20.57 (8.9) | 15.66 (4.9) | 9.4 (3.9) | 0.37 | F(2,97) = 28.39 p < 0.001 **, H > ARMS > Sch |
| P300 Latency (msec):T3 | 327.8 (35.9) | 325.5 (32.5) | 347.1 (52.9) | 0.07 | F(2,97) = 2.78, p = 0.067, n.s. |
| T4 | 326.3 (29.5) | 320.1 (39.0) | 343.4 (52.6) | 0.06 | F(2,97) = 2.88, 0.061, n.s. |
| Fz | 323.6 (30.9) | 322.9 (38.6) | 343.9 (52.7) | 0.05 | F(2,97) = 2.76, p = 0.068, n.s. |
| Cz | 314.8 (29.1) | 315.3 (36.1) | 340.5 (52.2) | 0.08 | F(2,97) = 4.43, p = 0.014 *, H, ARMS < Sch |
| Pz | 313.5 (29.5) | 314.9 (32.5) | 339.0 (45.7) | 0.10 | F(2,97) = 5.17, p = 0.007 **, H, ARMS < Sch |
Values represent mean (SD). ARMS; at-risk mental state, H; healthy controls, Sch; schizophrenia. JART; Japanese Adult Reading Test, PANSS; Positive and Negative Syndrome Scale, mGAF; modified Global Assessment Functioning. P300 data represent peak amplitudes (µV) and latencies (msec) for each group [mean (SD)]. All participants were antipsychotic-free at the time of measurement P300. Demographic differences between groups were examined with one-way analysis of variance (ANOVA), Student’s t-test or the chi-square test (* p < 0.05, ** p < 0.01). Effect sizes are represented in η2. a BACS and JART data were missing for some healthy control patients. b BACS was standardized by creating z-scores, with the mean score of Japanese healthy controls set to zero and the standard deviation set to one [45]. c BACS composite score was calculated by averaging all z-scores of the six primary measures from the BACS [46].