Table 1.
Comparison of demographic, clinical, and cognitive characteristics of healthy comparison subjects versus schizophrenia patients.
| Normal Comparison Subjects (N = 127) | Schizophrenia (N = 127) | t or X2 | df | p-level | |
|---|---|---|---|---|---|
| Demographic characteristics | |||||
| Age (years) | 52.1 (8.5) | 52.8 (7.1) | 0.72 | 245.0 | .471 |
| Education | 5.31 | 4 | .257 | ||
| ≤ 8 years | 5.5% | 4.9% | |||
| 9 to 11 years | 14.2% | 22.8% | |||
| 12 years | 42.5% | 43.9% | |||
| 13 to 15 years | 20.5% | 18.7% | |||
| ≥ 16 years | 17.3% | 9.8% | |||
| Gender (% men) | 57.5% | 64.6% | 1.34 | 1 | .247 |
| Ethnic Background | 0.19 | 2 | .909 | ||
| (non-Hispanic) Caucasian | 81.1% | 80.3% | |||
| African American | 11.0% | 12.6% | |||
| Other | 7.9% | 7.1% | |||
| Clinical characteristics | |||||
| Psychiatric diagnosis | |||||
| % Schizophrenia | n/a | 66.2 | |||
| % Schizoaffective Disorder | n/a | 33.8 | |||
| Severity of psychopathology (PANSS subscale scores) | |||||
| Positive subscale total | n/a | 14.4 (6.0) | |||
| Negative subscale total | n/a | 13.4 (4.7) | |||
| General subscale total | n/a | 27.4 (7.7) | |||
| Cognitive performance | |||||
| Verbal Comprehension Index | 100.2 (13.7) | 86.4 (14.9) | 7.71 | 252.0 | <.001 |
| Perceptual Organization Index | 99.2 (13.3) | 79.1 (11.6) | 12.81 | 250.0 | <.001 |
| Processing Speed Index | 99.3 (13.6) | 73.7 (10.1) | 17.00 | 232.2 | <.001 |
| Working Memory Index | 100.3 (13.8) | 79.3 (15.8) | 11.21 | 249.0 | <.001 |
| Auditory Memory Index | 100.3 (14.7) | 78.0 (15.3) | 11.87 | 252 | <.001 |
| Visual Memory Index | 99.6 (14.8) | 67.7 (13.2) | 18.02 | 248 | <.001 |
Note: Values represent means (and SDs) for continuous variables or proportions (percent) for categorical variables. Differences between groups are calculated via t-tests for continuous variables and chi-squares for categorical variables.
Key to abbreviations: n/a = not applicable; PANSS = Positive and Negative Syndrome Scale