Table 1.
Comparison of Normal Subjects and Persons with Early- Versus Late-Onset Schizophrenia on Demographic, Clinical, Cognitive, and Functional Measures
| N (NC, EOS, LOS) | Normal Comparison Subjects (NC) | Early- Onset Schizophrenia (EOS) | Late-Onset Schizophrenia (LOS) | F, t, or X2 | df | p | Pairwise Significant Differences | |
|---|---|---|---|---|---|---|---|---|
| Demographic characteristics | ||||||||
| Age (years) | (359,744,110) | 59.8 (14.5) | 51.0 (8.3) | 57.6 (8.7) | 75.5 | 2,278 | <.001 | EOS<LOS=NC |
| Education (years) | (359, 738,110) | 13.9 (2.3) | 12.2 (2.4) | 12.5 (3.1) | 64.6 | 2,277 | <.001 | LOS=EOS<NC |
| Gender (% women) | (359, 744,110) | 63% | 34% | 47% | 84.0 | 2 | <.001 | NC>LOS>EOS |
| Ethnic background % Caucasian | (359, 744,110) | 70% | 64% | 66% | 3.6 | 2 | .163 | |
| Marital status | (358, 736,110) | 208.6 | 4 | <.001 | EOS≠LOS EOS≠NC LOS≠NC |
|||
| Divorced/Widowed/Separated | 41% | 41% | 55% | |||||
| Married/Cohabitating | 43% | 10% | 16% | |||||
| Single | 16% | 49% | 29% | |||||
| Clinical characteristics | ||||||||
| Age of illness onset (years) | (n/a, 744,110) | n/a | 22.9 (7.4) | 48.1 (7.3) | n/aa | n/aa | n/aa | |
| % Paranoid subtype | (n/a, 541,71) | n/a | 33% | 36% | 0.2 | 1 | .615 | |
| Duration of illness (years) | (n/a, 744,110) | n/a | 28.1(10.2) | 9.4 (7.6) | n/aa | /n/aa | n/aa | |
| Daily dose of antipsychotic medication (mg chlorpromazine equivalent) | (n/a, 485, 65) | n/a | 477 (888) | 135 (96) | −8.1 | 541.2 | 0.002 | |
| Abnormal Involuntary Movement Scale score | (168, 637,101) | 1.8 (1.9) | 4 (3.7) | 4.4 (4.6) | 150.6 | 2,234 | <.001 | NC<EOS=LOS |
| Positive and Negative Syndrome Scale | ||||||||
| Positive Syndrome score | (356, 740,110) | 8.3 (1.9) | 15.5 (6.1) | 14.0 (6) | 367.9 | 2,278 | <.001 | NC<LOS<EOS |
| Negative Syndrome score | (355, 741,109) | 8.2 (1.7) | 15.0 (5.6) | 14.0 (5.3) | 545.0 | 2,272 | <.001 | NC<LOS=EOS |
| General Psychopathology score | (354, 740,109) | 19.3 (3.1) | 30.2 (8.5) | 27.9 (6.6) | 482.1 | 2,291 | <.001 | NC<LOS<EOS |
| Proxy for Deficit Syndrome (PDS) scoreb | (743,110) | n/a | n/a | −6.5 (3.5) | 72.7 | 2,292 | <.001 | EOS=LOS |
| % with Deficit Syndrome (PDS ≥ −2 defining Deficit Syndrome status) b.59 | (743, 110) | n/a | n/a | 6.4% | 1.18 | 1 | .278 | EOS=LOS |
| Hamilton Rating Scale for Depression score | (354, 688,110) | 3.6 (3.7) | 10.4 (6.4) | 9.7 (6.1) | 218.7 | 2,295 | <.001 | NC<EOS=LOS |
| Cognitive performance | ||||||||
| WAIS-R or WAIS-III (Reference group Scaled Scores) | ||||||||
| Information | (152, 270,54) | 10.4 (2.7) | 9.4 (3.2) | 9.2 (3.2) | 49.9 | 2,139 | <.001 | EOS=LOS<NC |
| Vocabulary | (165, 299,56) | 11.1 (2.8) | 8.4 (3.2) | 8.9 (3.1) | 42.4 | 2,149 | <.001 | EOS=LOS<NC |
| Similarities | (145, 284,56) | 10.1 (2.7) | 7.9 (3.3) | 8 (3.3) | 71.2 | 2,146 | <.001 | EOS=LOS<NC |
| Picture Arrangement | (147, 270,53) | 8 (2.8) | 6.8 (2.9) | 6.6 (3.2) | 31.9 | 2,135 | <.001 | EOS=LOS<NC |
| Block Design | (146, 263,55) | 7.9 (2.5) | 6.5 (2.4) | 7 (3.1) | 56.4 | 2,135 | <.001 | EOS<LOS<NC |
| Arithmetic | (148, 276,57) | 9.1 (2.8) | 7.1 (2.8) | 7.6 (3.5) | 52.3 | 2,141 | <.001 | EOS=LOS<NC |
| Digit Symbol | (150, 431,70) | 7 (2.4) | 4.7 (1.8) | 5.3 (2.4) | 140.3 | 2,155 | <.001 | EOS<LOS<NC |
| WCST Perseverative Responses (T-score) | (155, 362,62) | 49.8 (12.9) | 39.3 (13.2) | 45 (15.7) | 31.4 | 2,151 | <.001 | EOS<LOS<NC |
| California Verbal Learning Test (CVLT) | (157, 197,42) | 10.1 (3.3) | 9.2 (3.6) | 10.7 (3.4) | 3.9 | 2,117 | .023 | EOS<LOS=NC |
| Functional capacity and Quality of life | ||||||||
| UCSD Performance-based Skills Assessment score | (31, 417,53) | 92.6 (5.8) | 67.6 (20.6) | 72 (18.8) | 112.4 | 2,71 | <.001 | EOS<LOS<NC |
| Social Skills Performance Assessment score | (110, 462,56) | 37.3 (4) | 26.4 (8) | 28.4 (8.2) | 416.8 | 2,133 | <.001 | EOS<LOS<NC |
| Quality of Well-Being scale (Adjusted score) | (158, 494,77) | 0.7 (0.1) | 0.5 (0.1) | 0.6 (0.1) | 99.2 | 2,179 | <.001 | EOS<LOS<NC |
Note: Higher scores on Abnormal Involuntary Movement Scale, Positive and Negative Syndrome Scale, and Hamilton Rating Scale for Depression represent worse symptoms. Higher scores on the Proxy for Deficit Syndrome, as well as all the cognitive, functional capacity, and Quality of Well-Being measures represent better status.
Means (and SDs) for age of onset and duration of illness are provided for descriptive purposes only. The significance of these differences was not statistically tested because the null hypotheses (no difference in the EOS versus LOS populations) are, by definition, known to be false.
Deficit syndrome measures were not applied to normal comparison subjects.
Abbreviations:
EOS = Early-Onset Schizophrenia
LOS = Late-Onset Schizophrenia
n/a = not applicable
NC = Normal Comparison subject
UCSD = University of California, San Diego
WAIS-R = Wechsler Adult Intelligence Scale – Revised
WAIS-III = Wechsler Adult Intelligence Scale – Third Edition