Table 1 Demographic and baseline clinical characteristics

Mean age ± SD (years)

47.0 ± 10.2

47.8 ± 10.6

0.65

Female, n (%)

72 (74.2%)

47 (79.7%)

0.56

White, n (%)

93 (95.9%)

56 (94.9%)

1

Mean age ± SD at initial onset of depressive symptoms (years)

20.0 ± 11.5

18.9 ± 9.2

0.51

Mean age ± SD at initial diagnosis of depression (years)

26.9 ± 10.6

27.9 ± 11.6

0.59

Lifetime number of diagnosed depressive episode

20.7 ± 29.2

13.7 ± 23.2

0.10

Psychiatric hospitalizations within the 5 years prior to registry enrollment

3.6 ± 5.4

1.5 ± 2.1

 < 0.001

Lifetime suicide attempts

2.7 ± 4.8

1.5 ± 2.9

0.05

DSM-IV-TR primary diagnosis, n (%)

 Bipolar I disorder, currently moderately severe major depressive episode

19 (19.6%)

18 (30.6%)

0.17

 Bipolar I disorder, currently severe major depressive episode

46 (47.4%)

10 (16.9%)

 < 0.001

 Bipolar II disorder, currently depressed

32 (33.0%)

31 (52.5%)

0.025

Baseline scores, n (%)

 Montgomery–Åsberg Depression Rating Scale

33.7 ± 7.3

29.7 ± 5.9

 < 0.001

 Clinical Global Impression—Severity

5.2 ± 0.8

4.7 ± 0.7

 < 0.001

 Quick Inventory of Depressive Symptomatology-Self Report

18.4 ± 4.9

15.9 ± 5.2

0.004

 Suicidality-based on MADRS Item 10

2.7 ± 1.4

2.0 ± 1.2

0.003