Table 2.
Cognitive performance in the overall sample and differences between FEP participants and healthy controls.
| Test | Subtest | Domain |
M (SD) |
t | df | p | Effect size estimate | ||
|---|---|---|---|---|---|---|---|---|---|
| Total (N = 129) |
FEP (n = 86) |
Controls (n = 43) |
|||||||
| WRAT-4 WAIS-III |
Word Readinga | Premorbid IQ | 101.6 (15.4) | 97.2 (14.5) | 109.6 (13.6) | 4.55 | 116 | <0.001 | 0.88 |
| Full Scale IQa | Current IQ | 97.3 (14.6) | 91.5 (13.5) | 107.6 (10.0) | 7.36 | 106.58c | <.001b | 1.36 | |
| Picture Completiona | Visual perception and reasoning | 9.1 (2.7) | 8.7 (2.7) | 9.9 (2.4) | 2.55 | 118 | .010b | 0.50 | |
| Informationa | Acquired general knowledge | 10.1 (3.3) | 8.7 (3.0) | 12.6 (2.0) | 8.84 | 112.83c | <.001b | 1.59 | |
| Digit Span Forward | Attention span | 9.7 (2.0) | 9.4 (2.0) | 10.1 (1.9) | 1.97 | 117 | .043b | 0.38 | |
| Digit Span Backwards | Working memory | 6.8 (2.1) | 6.3 (2.0) | 7.8 (1.9) | 4.13 | 117 | <.001b | 0.79 | |
| Digit Symbol – Codinga | Speed of processing | 9.0 (3.1) | 8.1 (2.8) | 10.3 (3.1) | 3.90 | 104 | <0.001 | 0.77 | |
| Stroop | Stroop Colour-Word | Inhibition | 45.6 (12.1) | 43.0 (12.0) | 50.1 (11.0) | 3.17 | 113 | 0.002 | 0.62 |
| COWAT | Phonemic Total | Verbal fluency | 36.5 (11.7) | 33.8 (11.0) | 41.4 (11.5) | 3.51 | 116 | <.001b | 0.67 |
| Semantic Total | Verbal fluency | 21.6 (5.8) | 20.5 (6.3) | 23.6 (4.1) | 3.17 | 112.44c | 0.002 | 0.58 | |
| PAL | First Trial | Immediate verbal memory | 3.1 (2.3) | 2.5 (2.1) | 4.2 (2.2) | 4.22 | 117 | <.001b | 0.80 |
| Total of Three Trials | Immediate verbal learning | 14.2 (6.0) | 12.5 (5.8) | 17.5 (5.1) | 4.72 | 117 | <.001b | 0.92 | |
| Delayed Recall | Delayed verbal memory | 5.7 (2.1) | 5.1 (2.0) | 6.9 (1.6) | 5.02 | 100.70c | <.001b | 0.97 |
Notes. WRAT = Wide Range Achievement Test; WAIS = Wechsler Adult Intelligence Scale; COWAT = Controlled Oral Word Association Test; PAL = Paired Associate Learning Test. Bonferroni Correction = 0.05/13 = 0.0038. p values that remained significant after Bonferroni corrections are bolded. Effect size estimate = Cohen's d.
Refers to tests using scores scaled according to participants' age (for Estimated Premorbid IQ and Estimated Full Scale IQ: population M = 100, and SD = 15; for Picture Completion, Information, and Digit Symbol – Coding: population M = 10, and SD = 3).
Independent Samples Mann-Whitney U test (non-parametric) p values for variables not meeting normality assumptions of parametric t-test.
Equal variances not assumed.