Table 1.
The study sample of bipolar disorder twins and co-twins.
| Affection status | Zygosity | Sex |
| Both twins participated, n = 54 | ||
| BP*-Healthy* | DZ | FF |
| BP*-Healthy* | DZ | FF |
| BP*-Healthy* | DZ | FF |
| BP*-Healthy* | DZ | MM |
| BP*-Healthy | DZ | MF |
| BP-Healthy* | DZ | MF |
| BP-Healthy* | DZ | FF |
| BP-Healthy* | DZ | FF |
| BP*-Healthy | DZ | FF |
| BP*-Healthy | MZ | FF |
| BP-Healthy* | DZ | FF |
| BP-Healthy* | DZ | FF |
| BP*-Healthy | DZ | FF |
| BP-Healthy | DZ | MM |
| BP-Healthy | MZ | MM |
| BP-Alcohol abuse | DZ | MM |
| BP-Alcohol abuse* | DZ | FF |
| BP*-MDD | DZ | FM |
| BP*-Schizophrenia* | MZ | MM |
| BP*-MDD* | DZ | FF |
| BP*-MDD* | DZ | FF |
| BP*-BP* | MZ | FF |
| BP*-BP* | DZ | FF |
| BP*-BP | MZ | MM |
| BP*-BP | DZ | MM |
| BP-BP | MZ | MM |
| Healthy-Healthy | MZ | FF |
| One twin participated, n = 13 (Co-twin did not participate, n = 13) | ||
| BP*-(Schizophrenia) | DZ | MM |
| BP*-(BP) | DZ | MM |
| BP*-(Healthy) | DZ | MM |
| BP-(Alcohol abuse) | DZ | MM |
| Healthy-(BP) | DZ | MM |
| Healthy-(BP) | DZ | MM |
| BP-(Healthy) | DZ | MM |
| Healthy-(BP) | DZ | MM |
| BP-(BP) | DZ | MM |
| MDD-(BP) | MZ | FF |
| Post-partum depression-(BP) | DZ | FM |
| BP-(Schizophrenia) | DZ | FM |
| BP-(BP) | DZ | MM |
*Subjects who filled in the MEQ in 2002, n = 36. Abbreviations: BP = bipolar disorder, MDD = major depressive disorder, DZ = dizygotic, MZ = monozygotic, M = male, F = female.