Participants demographic and clinical characteristics and the results of pairwise group comparisons
| Group; mean ± SD or no. (%)* | Comparison; p value | |||||
|---|---|---|---|---|---|---|
| Characteristic | Control, n = 85 | BDI, n = 81 | BDII, n = 59 | BDI v. BDII | BDII v. control | BDI v. control |
| Age, yr | 39 ± 15 | 40 ± 12 | 40 ± 13 | 0.83 | 0.59 | 0.72 |
| Male sex | 41 (48) | 36 (44) | 16 (27) | 0.036 | 0.011 | 0.63 |
| No. manic episodes, median (IQR)† | — | 2 (3) | — | — | — | — |
| No. depression episodes, median (IQR)† | — | 10 (15) | 18 (41) | 0.003 | — | — |
| BMI | 24 ± 4 | 26 ± 5 | 25 ± 4 | 0.06 | 0.34 | 0.001 |
| Duration of illness, yr | — | 18 ± 10 | 21 ± 14 | 0.16 | — | — |
| Age at onset, yr | — | 22 ± 9 | 19 ± 11 | 0.19 | — | — |
| Education, yr (categorized), median (IQR)† | 3 (2) | 3 (2) | 3 (2) | 0.27 | 0.76 | 0.35 |
| CGI-S | — | 4.48 ± 1.42 | 3.83 ± 1.17 | 0.005 | — | — |
| Smoker | 15 (18) | 24 (30) | 19 (32) | 0.75 | 0.014 | 0.023 |
| Moist snuff | 9 (11) | 18 (22) | 7 (12) | 0.13 | 0.62 | 0.02 |
| Alcohol misuse | — | 13 (16) | 6 (10) | 0.33 | — | — |
| Drug misuse | — | 7 (9) | 6 (10) | 0.74 | — | — |
| Medication use | ||||||
| Lithium | — | 56 (69) | 20 (34) | < 0.001 | — | — |
| Antiepileptics | — | 26 (32) | 21 (36) | 0.67 | — | — |
| Antidepressants | — | 32 (40) | 36 (61) | 0.011 | — | — |
| Antipsychotics | — | 33 (41) | 6 (10) | 0.001 | — | — |
| Comorbid disorders | ||||||
| ADHD | — | 18 (22) | 17 (29) | 0.40 | — | — |
| Panic disorder | — | 24 (30) | 20 (48) | 0.55 | — | — |
| Social phobia | — | 13 (16) | 10 (34) | 0.86 | — | — |
| OCD | — | 10 (48) | 8 (14) | 0.81 | — | — |
| GAD | — | 13 (12) | 9 (15) | 0.93 | — | — |
| PTSD | — | 5 (6) | 2 (3) | 0.49 | — | — |
| Anorexia | — | 5 (6) | 7 (12) | 0.23 | — | — |
| Bulimia | — | 7 (9) | 5 (8) | 0.99 | — | — |
| Psychosis | — | 65 (80) | 4 (7) | < | 0.001 | — |
| Schizophrenia | — | 1 (1) | 2 (3) | 0.38 | — | — |
| Intracranial volume (L) | 1.57 ± 0.14 | 1.58 ± 0.18 | 1.54 ± 0.17 | 0.18 | 0.26 | 0.80 |
ADHD = attention-deficit/hyperactivity disorder; BDI/BDII = bipolar disorder subtypes I and II; BMI = body mass index; CGI-S = Clinical Global Impression; GAD = generalized anxiety disorder; ICV = intracranial volume; IQR = interquartile range; OCD = obsessive–compulsive disorder; PTSD = posttraumatic stress disorder; SD = standard deviation.
↵* Unless indicated otherwise.
↵† Significance was determined with the nonparametric Mann–Whitney U test.