Demographic, psychopathological and clinical characteristics of study participants
| Group; mean ± SD* | ||||
|---|---|---|---|---|
| Characteristic | Schizophrenia, n = 27† | Control, n = 25 | Statistical test‡ | p value |
| Age, yr | 31.9 ± 7.1 | 33.0 ± 9.7 | U = 322.00 | 0.78 |
| Sex, female:male | 9:18 | 9:16 | χ2 = 0.04 | 0.81 |
| Education, yr | 12.2 ± 3.0 | 12.4 ± 3.6 | U = 334.00 | 0.95 |
| Duration of illness, yr | 9.2 ± 6.6 | — | — | — |
| Age of onset, yr | 22.7 ± 6 | — | — | — |
| Chlorpromazine equivalents, mg/d | 491.3 ± 349.5 | — | — | — |
| BNSS score | ||||
| Apathy (motivation and pleasure) | 14.8 ± 6.8 | — | — | — |
| Diminished expression | 9.8 ± 7.4 | — | — | — |
| SANS score§ | ||||
| Apathy | 12.8 ± 5.1 | — | — | — |
| Diminished expression | 12.6 ± 10.7 | — | — | — |
| PANSS score¶ | ||||
| Positive | 6.6 ± 2.5 | — | — | — |
| Negative | 13.6 ± 5.2 | — | — | — |
| Disorganized | 4.5 ± 2.2 | — | — | — |
| Excited | 5.1 ± 1.5 | — | — | — |
| Depressed | 5.1 ± 2.2 | — | — | — |
| Total | 49.4 ± 11.2 | — | — | — |
| CDSS total score | 1.5 ± 2.2 | — | — | — |
| GAF score | 56.9 ± 9.6 | — | — | — |
| PSP total score | 56.4 ± 9.9 | — | — | — |
| Cognition (Composite Cognitive Ability)** | 0.61 ± 0.89 | 0 ± 0.53 | t = 3.0 | 0.010 |
| MWT IQ | 25.9 ± 5.8 | 27.6 ± 4.0 | t = 1.2 | 0.23 |
BNSS = Brief Negative Symptom Scale; CDSS = Calgary Depression Scale for Schizophrenia; GAF = Global Assessment of Functioning; MWT IQ = Multiple Word Test Intelligence Quotient; PANSS = Positive and Negative Syndrome Scale; PSP = Personal and Social Performance Scale; SANS = Scale for the Assessment of Negative Symptoms; SD = standard deviation.
↵* Unless otherwise indicated.
↵† All patients were receiving atypical antipsychotics at the time of testing.
↵‡ Potential group differences were investigated using 2-sample t tests for continuous and χ2 tests for categorical data. For non-normally distributed data Mann–Whitney U tests were applied.
↵§ Apathy includes avolition/apathy and anhedonia/asociality; diminished expression includes affective flattening or blunting and alogia.
↵¶ Positive factor = P1, P3, P5, G9; negative factor = N1, N2, N3, N4, N6, G7; disorganized factor = P2, G5, N11; excited factor = P4, P7, G8, G14; depressed factor = G2, G3, G6.
↵** Cognition data have been z-transformed based on the data of the control group for each test separately. The Composite Cognitive Ability score was computed as the mean of the z-transformed test scores at the participant level.