Table 1.
Demographic Characteristics (Mean/SD) of the Study Sample
| Group | N | Age | Gender (% Male) | Years of Education | Duration of Illnessa | BPRSb | GASc |
|---|---|---|---|---|---|---|---|
| Schizophrenia (SZ) patients | 242 | 38.7 (9.5) | 55.0%d | 14.0 (2.3)e | 15.6 (9.7)f | 48.0 (14.7)g | 37.4 (9.8)h |
| Bipolar patients | 79 | 35.8 (10.4) | 36.7% | 15.4 (2.4) | 11.2 (9.5) | 34.3 (9.2) | 51.1 (11.7) |
| Normal control subjects | 184 | 39.1 (15.0) | 40.8% | 15.0 (2.4) | — | — | — |
| Relatives of SZ patients | 272 | 51.3 (16.7)i | 34.2% | 15.3 (2.6) | — | — | — |
| Relatives of bipolar patients | 40 | 42.0 (12.1) | 22.5% | 15.6 (2.5) | — | — | — |
Note: RelSZ, relatives of schizophrenia patients; RelBP, relatives of bipolar disorder patients; GAS, Global Assessment Scale; BPRS, Brief Psychiatric Rating Scale.
aDuration of illness is defined as number of years since first hospitalization.
bBPRS was missing for 4 SZ and 1 BP.
cGAS was missing for 1 SZ and 1 BP.
dSZ patients were disproportionately male compared with normal controls (P = .040), RelSZ (P < .001), and RelBP (P = .003); the difference between the proportion of men in the SZ and BP groups did not reach statistical significance (P = .05).
eSZ patients had significantly fewer years of education compared to all other groups (P < .001 for each pairwise comparison).
fSZ patients had significantly longer duration of illness compared to BP (P = .001).
gSZ patients had significantly higher BPRS than BP (P < .001).
hSZ patients had significantly lower GAS than BP (P < .001).
iRelSZ were significantly older than all other groups (P < .001 for each pairwise comparison using the Tukey-Kramer test).