Table 3a.
Effect of single environmental risk factors on measures of aggressive behavior in schizophrenic and general population subjects
| Perinatal hit | p value (χ2/Z) | Urbanicity | p value (χ2/Z) | Migration | p value (χ2/Z) | ||||
|---|---|---|---|---|---|---|---|---|---|
| No | Yes | Rural | Urban | No | Yes | ||||
| Discovery sample (N = 134) | |||||||||
| Male schizophrenic subjects | n = 77 | n = 57 | n = 66 | n = 68 | n = 114 | n = 20 | |||
| History of forensic hospitalization | 12 (15.6%) | 10 (17.5%) | p = 0.762 (χ2 = 0.09) | 7 (10.6%) | 15 (22.1%) | p = 0.074 (χ2 = 3.20) | 12 (10.5%) | 10 (50.0%) | p = 0.0001† (χ2 = 19.32) |
| Aggression proxya | 18 (23.4%) | 19 (33.3%) | p = 0.202 (χ2 = 1.63) | 11 (16.7%) | 26 (38.2%) | p = 0.005 (χ2 = 7.80) | 21 (18.4%) | 16 (80.0%) | p = 1.3 x 10−8 (χ2 = 32.28) |
| Violent aggression severity score (VASS) | 23.01 (37.43) | 35.17 (39.23) | p = 0.003 (Z = −2.96) | 22.86 (38.29) | 33.35 (38.35) | p = 0.019 (Z = −2.35) | 23.16 (33.73) | 56.83 (51.12) | p = 0.0005 (Z = −3.46) |
| Aggression before schizophreniab | 25 (32.5%) | 34 (59.6%) | p = 0.002 (χ2 = 9.82) | 24 (36.4%) | 35 (51.5%) | p = 0.078 (χ2 = 3.10) | 46 (40.4%) | 13 (65.0%) | p = 0.041 (χ2 = 4.20) |
| Replication sample I (N = 438–606) | |||||||||
| GRAS I male schizophrenic subjects | n = 374–381 | n = 222–223 | n = 262–266 | n = 176–178 | n = 542–550 | n = 56 | |||
| History of forensic hospitalization | 51 (13.6%) | 25 (11.3%) | p = 0.201 (χ2 = 0.71) | 28 (10.7%) | 25 (14.2%) | p = 0.134 (χ2 = 1.23) | 59 (10.9%) | 17 (30.4%) | p = 1.6 x 10−5 (χ2 = 17.35) |
| Aggression proxya | 81 (21.3%) | 48 (21.5%) | p = 0.470 (χ2 < 0.01) | 43 (16.2%) | 45 (25.3%) | p = 0.009 (χ2 = 5.58) | 102 (18.5%) | 27 (48.2%) | p = 1.2 x 10−7 (χ2 = 26.70) |
| Replication sample II (N = 316–320) | |||||||||
| GRAS II male schizophrenic subjects | n = 219–220 | n = 99 | n = 182–183 | n = 134 | n = 282–283 | n = 37 | |||
| History of forensic hospitalization | 55 (25.1%) | 25 (25.3%) | p = 0.490 (χ2 < 0.01) | 41 (22.5%) | 39 (29.1%) | p = 0.092 (χ2 = 1.77) | 65 (23.0%) | 15 (40.5%) | p = 0.011 (χ2 = 5.33) |
| Aggression proxya | 64 (29.1%) | 28 (28.3%) | p = 0.442 (χ2 = 0.02) | 45 (24.6%) | 47 (35.1%) | p = 0.021 (χ2 = 4.13) | 76 (26.9%) | 16 (43.2%) | p = 0.019 (χ2 = 4.29) |
| Replication sample III (N = 424–503) | |||||||||
| GRAS I–II female schizophrenic subjects | n = 269–300 | n = 200 | n = 267–268 | n = 157–159 | n = 450–454 | n = 49 | |||
| History of forensic hospitalization | 11 (3.7%) | 5 (2.5%) | p = 0.234 (χ2 = 0.53) | 6 (2.2%) | 7 (4.4%) | p = 0.166† (χ2 = 1.58) | 14 (3.1%) | 2 (4.1%) | p = 0.474† (χ2 = 0.14) |
| Aggression proxya | 33 (11.1%) | 23 (11.5%) | p = 0.452 (χ2 = 0.02) | 25 (9.4%) | 20 (12.7%) | p = 0.138 (χ2 = 1.19) | 48 (10.7%) | 8 (16.3%) | p = 0.117 (χ2 = 1.42) |
| Replication sample IV–V (N = 513–551) | |||||||||
| General population | NA | NA | NA | NA | n = 517–521 | n = 25–26 | |||
| Secondary psychopathy score – LSRPc | NA | NA | NA | NA | 19.79 (3.53) | 20.96 (3.30) | p = 0.047 (Z = −1.68) | ||
| Aggression-hostility score – ZKPQd | NA | NA | NA | NA | 24.25 (4.04) | 24.81 (4.55) | p = 0.344 (Z = −0.40) | ||
Data are uncorrected means (SD) or n (%); for statistical analysis, Mann-Whitney-U, χ2, or Fisher’s exact test was used; significant p values are underlined; for replication samples, testing was one-sided; because of missing data, sample sizes vary;
aany conviction for battery, sexual assault, manslaughter and murder, or a history of forensic hospitalization;
bdeviant behavior, criminality, verbal, physical, or sexual aggression at least half a year (mean=13.69 years, SD=10.10) before first psychotic episode;
cLSRP=Levenson Self-Report Psychopathy Scale;
dZKPQ-50-CC=Zuckerman-Kuhlman Personality Questionnaire;
†Fisher’s exact test upon group size estimations <5; NA=information not available.