Table 1 Demographic characteristics
| Â | Bipolar twins (BD) | Control twins (HC) | ||||||
|---|---|---|---|---|---|---|---|---|
Total (n = 52) | MZ (n = 22) | DZ (n = 30) | Index (n = 26) | Co-twin (n = 26) | Total (n = 54) | MZ (n = 30) | DZ (n = 24) | |
Age, mean (SD), range, y | 49.6 (10.2), 29–69 | 47.5 (11.0), 29–62 | 51.1 (9.5), 37–69 | 49.6 (10.2), 29–69 | 47.5, (11.0), 29–62 | 48.3 (8.4), 32–72 | 48.5 (10.2), 32–72 | 48.1 (6.0), 39–57 |
Female, n (%) | 37 (71.2) | 18 (81.8) | 19 (63.3) | 19 (73.1) | 18 (69.2) | 38 (70.3) | 24 (80.0) | 14 (58.3) |
Diagnosis | ||||||||
 Bipolar disorder I | 20 | 7 | 13 | 20 | – | – | – | – |
 Bipolar disorder II | 9 | 6 | 3 | 6 | 3 | – | – | – |
 Bipolar Disorder | 1 | – | 1 | – | 1 | – | – | – |
NOS | ||||||||
 Unipolar disorder | 4 | 3 | 1 | – | 4 | 2 | 0 | 2 |
 Psychotic disorder | 3 | 1 | 2 | – | 3 | – | – | – |
 Other disorder | 4 | 1 | 3 | – | 4 | 8 | 4 | 4 |
 No disorder | 11 | 4 | 7 | – | 11 | 45 | 27 | 18 |
Mood | ||||||||
 Euthymic | 17 | 8 | 9 | 14 | 3 |  |  |  |
 Mood episode | 11 | 5 | 6 | 10 | 1 |  |  |  |
 Missing data | 24 | 9 | 15 | 2 | 22 |  |  |  |
 Age at onset, mean (SD), range, y | 26.9 (10.3), 13–57 | 24.4 (7.8), 13–40 | 29.4 (11.9), 14–57 | 29.6 (10.7), 16–57 | 22.3 (7.5), 13–40 |  |  |  |
 Smoking, n (%) | 28 (53.8) | 10 (45.5) | 18 (60.0) | 17 (65.4) | 11 (42.3) | 27 (50.0) | 15 (50.0) | 12 (50.0) |
 Body mass index, mean (SD) range | 25.1 (4.4), 17–42 | 25.5 (4.7), 18–42 | 24.9 (4.1), 17–28 | 26.1 (5.0), 17–42 | 24.2 (3.4), 18–31 | 25.2 (4.7), 18–40 | 24.4 (3.4), 19–30 | 26.2 (5.9), 18–40 |
Psychotropic medication | ||||||||
 Lithium | 16 | 7 | 9 | 14 | 2 | 0 | 0 | 0 |
 Anticonvulsants | 3 | 1 | 2 | 2 | 1 | 0 | 0 | 0 |
 Antipsychotics | 18 | 5 | 13 | 13 | 5 | 0 | 0 | 0 |
 Antidepressants | 10 | 4 | 6 | 7 | 3 | 1 | 1 | 0 |
 Benzodiazepines | 8 | 4 | 4 | 7 | 1 | 1 | 1 | 0 |