Table 2.
Descriptive Statistics of Predictor Variables in the NAPLS3a and NAPLS2 Samples That Were Found to Be Associated With Remission During the Elastic Net Regularization Feature Selection Process
| NAPLS3 | NAPLS2 | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Remitters | Nonremitters | Test Statistic | P Value | Remitters | Nonremitters | Test Statistic | P Value | |||||
| Variable | N | Mean (SD) | N | Mean (SD) | t/χ 2 (df) | N | Mean (SD) | N | Mean (SD) | t/χ 2 (df) | ||
| Suspiciousness/ persecutory ideas | 75 | 2.68 (1.47) | 493 | 3.16 (1.33) | t(93.4) = 2.7 | .009 | 94 | 2.11 (1.48) | 459 | 2.86 (1.49) | t(134.5) = 4.5 | <.001 |
| Trouble with focus/ attention | 75 | 2.23 (1.29) | 493 | 2.64 (1.3) | t(98.2) = 2.6 | .01 | 94 | 2.33 (1.28) | 459 | 2.75 (1.24) | t(131.4) = 2.9 | .004 |
| Unusual thought content/delusional ideas | 75 | 3.56 (1.08) | 493 | 3.77 (1.02) | t(95.1) = 1.6 | .11b | 94 | 2.78 (1.54) | 459 | 3.46 (1.25) | t(119.3) = 4.1 | <.001 |
| Impaired tolerance to normal stress | 75 | 2.28 (1.83) | 493 | 2.98 (1.89) | t(99.3) = 3.1 | .003 | 94 | 2.41 (1.95) | 459 | 2.81 (1.86) | t(129.9) = 1.8 | .07 |
| Guilty ideas of reference | 75 | 0.24 (0.54) | 493 | 0.41 (0.71) | t(117.2) = 2.4 | .02 | 94 | 0.3 (0.62) | 459 | 0.41 (0.72) | t(148.7) = 1.6 | .12 |
| Decreased ideational richness | 75 | 0.88 (1.17) | 493 | 1.23 (1.28) | t(102.6) = 2.3 | .02 | 94 | 0.96 (1.24) | 459 | 1.21 (1.33) | t(140.3) = 1.8 | .07 |
| Motor disturbances | 75 | 0.52 (0.89) | 493 | 0.97 (1.07) | t(109.5) = 3.9 | <.001 | 94 | 0.67 (1.08) | 459 | 0.9 (1.05) | t(131.4) = 1.8 | .07 |
| Early wakening | 75 | 0.31 (0.72) | 493 | 0.51 (0.88) | t(110.6) = 2.2 | .03 | 94 | 0.37 (0.82) | 459 | 0.38 (0.8) | t(132.2) = 0.05 | .96 |
| Impairment in personal hygiene | 75 | 0.48 (0.91) | 493 | 0.87 (1.27) | t(123.2) = 3.3 | .001 | 94 | 0.62 (1.17) | 459 | 0.81 (1.22) | t(137.5) = 1.4 | .16 |
Bold values indicate significant differences between remitters and non-remitters at the significance level of p = 0.05.
aNAPLS = North American Prodrome Longitudinal Study.
bAlthough “unusual thought content/delusional ideas” was selected as a significant predictor of remission in the feature selection process, the group means did not differ between remitters and nonremitters. The elastic net model fits multiple variables simultaneously and may select features that account for variance in a multivariable context but do not differ in a univariate context.