Table 1 Participants baseline characteristics.
Variable | Participants | Overall group difference | Pair-wise comparisons | ||
|---|---|---|---|---|---|
Controls (C) | Siblings (S) | Patients (P) | |||
Background characteristics | |||||
 Age, mean (SE) | 30.60 (0.39) | 27.70 (0.28) | 27.40 (0.27) | F = 24.0, p < 0.001 | P < C; S < C |
 Gender, male n (%) | 269 (46.1) | 477 (45.6) | 857 (75.4) | X2 = 240.97, p < 0.001 |  |
 Ethnicity, Caucasian n (%) | 523 (92.1) | 871 (83.6) | 871 (79.1) | X2 = 45.84, p < 0.001 |  |
 Years of education, mean (SE) | 15.6 (0.16) | 13.5 (0.12) | 12.4 (0.12) | F = 64.5, p < 0.001 | P < S & C; S < C |
 Marital status n (%) | |||||
  Not married | 319 (57.6) | 589 (57.5) | 960 (87.8) | X2 = 303.17, p < 0.001 | |
  Married/Living together | 219 (39.5) | 412 (40.2) | 104 (9.5) | ||
  Other (divorced and widowed) | 16 (2.9) | 24 (2.3) | 30 (2.7) | ||
 Estimated current IQ, mean (SE) | 109.61 (0.69) | 102.58 (0.52) | 94.81 (0.49) | F = 190.93, p < 0.001 | P < S & C; S < C |
 Premorbid adjustment, mean (SE) | 1.13 (0.03) | 1.11 (0.02) | 1.98 (0.02) | F = 448.7, p < 0.001 | P > S; P > C |
 Age onset illness, mean (SE) |  |  | 23.1 (0.23) |  |  |
 Duration of illness, mean (SE) |  |  | 4.98 (4.46) |  |  |
 Number of psychotic episodes, mean (SE) |  |  | 1.72 (1.17) |  |  |
 Use of antipsychoticsa n (%) | |||||
  Not currently using |  |  | 38 (5.22) |  |  |
  Currently using |  |  | 574 (78.85) |  |  |
  Unknown if currently using |  |  | 116 (15.93) |  |  |
 Type of antipsychotics n (%) | |||||
  Typical |  |  | 80 (10) |  |  |
  Atypical |  |  | 717 (90) |  |  |
 Cannabis use | 83 (14.4) | 192 (18.6) | 424 (38.2) | X2 = 156.80, p < 0.001 |  |
Polygenic risk score of SCZ, mean (SE) | |||||
 PRSSCZ (PT = 5 × 10–8) |  − 0.54 (0.69) |  − 0.39 (0.64) |  − 0.29 (0.69) | F = 16.40, p = 0.001 | P > C |
 PRSSCZ (PT = 0.05) |  − 453.72 (4.75) |  − 452.21 (4.61) |  − 450.16 (4.77) | F = 75.07, p < 0.001 | P > S & C; S > C |
 PRSSCZ (PT = 0.1) |  − 586.57 (5.50) |  − 584.94 (5.25) |  − 582.49 (5.49) | F = 75.70, p < 0.001 | P > S & C; S > C |
 PRSSCZ (PT = 0.5) |  − 902.40 (6.70) |  − 900.58 (6.43) |  − 897.62 (6.79) | F = 70.04, p < 0.001 | P > S & C; S > C |
Schizotypy, mean (SE) | |||||
 Positive | 0.30 (0.02) | 0.38 (0.01) |  | F = 59.45, p < 0.001 | S > C |
 Negative | 0.23 (0.01) | 0.27 (0.0.01) |  | F = 49.25, p < 0.001 | S > C |
Psychotic symptoms, mean (SE) | |||||
 Positive |  |  | 13.90 (0.20) |  |  |
 Negative |  |  | 14.99 (0.21) |  |  |
 Disorganization |  |  | 16.77 (0.20) |  |  |
 Emotional distress |  |  | 15.82 (0.18) |  |  |
 Excitement |  |  | 12.05 (0.13) |  |  |
Psychotic experiences, mean (SE) | |||||
Positive symptoms frequency | 0.19 (0.01) | 0.20 (0.01) | 0.67 (0.01) | F = 571.97, p < 0.001 | P > S & C |
 Positive symptoms distress | 0.43 (0.03) | 0.46 (0.02) | 1.25 (0.02) | F = 511.36, p < 0.001 | P > S & C |
 Negative symptoms frequency | 0.49 (0.02) | 0.54 (0.01) | 1.02 (0.01) | F = 401.58, p < 0.001 | P > S & C |
 Negative symptoms distress | 0.67 (0.02) | 0.68 (0.02) | 1.25 (0.02) | F = 305.75, p < 0.001 | P > S & C |
 Depressive symptoms frequencya | 0.58 (0.02) | 0.62 (0.02) | 1.00 (0.02) | F = 217.76, p < 0.001 | P > S & C |
 Depressive symptoms distressa | 0.88 (0.03) | 0.92 (0.02) | 1.44 (0.02) | F = 212.19, p < 0.001 | P > S & C |
 General cognition | 0.62 (0.07) | 0.13 (0.05) |  − 1.18 (0.05) | F = 312.77, p < 0.001 | P < S & C; S < C |
Functioning and quality of life, mean (SE) | |||||
 Occupational functioninga | 8.93 (0.13) | 8.92 (0.10) | 5.91 (0.10) | F = 292.98, p < 0.0001 | P < S & C |
 Social functioninga | 124.04 (0.36) | 122.32 (0.28) | 112.51 (0.27) | F = 474.62, p < 0.0001 | P < S & C; S < C |
 Global functioning |  |  | 54.50 (0.52) |  |  |
 Quality of life | 4.07 (0.02) | 3.97 (0.02) | 3.40 (0.02) | F = 492.16, p < 0.0001 | P < S & C; S < C |
