Table 4 Treatment response differences between patients diagnosed with bipolar I disorder (N = 587) and bipolar II disorder (N = 221). Pearson’s chi-squared tests (or Fisher’s exact test [*]) has been used for categorical variables, Wilcoxon rank-sum test for continuous variables. P < 0.05 are shown in bold. Pairwise Fisher’s exact test was used for post-hoc comparisons of multinomial variables, using Benjamini–Hochberg procedure as false discovery rate (FDR) correction method. Pairwise significant differences (FDR-p < 0.05) between individual categories are indicated with lowercase letters. Abbreviations: M = median; IQR = interquartile range; SMD = standardized mean difference

Lithium responders

157 (37.2)

53 (35.1)

0.044

0.717

A score (improvement)

8.00 [4.00, 9.00]

6.50 [3.25, 9.00]

0.161

0.153

B1 score: number of episodes before/off treatment

0.296

0.019

 4 or more episodes

291 (74.8)

124 (85.5)

 2 or 3 episodes

67 (17.2)

17 (11.7)

 1 episode

31 (8.0)

4 (2.8)

B2 score: frequency of episodes before/off treatment

0.215

0.128

 Average to high, including rapid cycling

296 (76.1)

119 (82.1)

 Low, spontaneous remissions of 3 or more years

65 (16.7)

22 (15.2)

 1 episode only, risk not known

28 (7.2)

4 (2.8)

 B3 score: duration of the treatment

0.169

0.191

  2 or more years

336 (86.4)

117 (80.7)

  1–2 years

33 (8.5)

15 (10.3)

  Less than 1 year

20 (5.1)

13 (9.0)

 B4 score: compliance during period(s) of stability

0.268

0.062

 Excellent, e.g., documented by drug levels

342 (88.1)

132 (91.7)

 Good, more than 80% levels in the therapeutic range

26 (6.7)

11 (7.6)

 Poor, repeatedly off treatment

20 (5.2)

1 (0.7)

B5 score: use of additional medication during the period(s) of stability

0.263

0.032

 None except infrequent sleep medications

116 (29.9)

41 (28.3)

 Low-dose antidepressants or antipsychotics, or prolonged use of sleep medications

101 (26.0)

24 (16.6)

a

 Prolonged or systematic use of antidepressants or antipsychotics

171 (44.1)

80 (55.2)

a

Total score

5.00 [1.00, 8.00]

4.00 [1.00, 8.00]

0.071

0.522

Valproic acid treatment response

Valproic acid responders*

18 (14.0)

2 (4.9)

0.315

0.165

A score (improvement)

7.00 [4.00, 8.00]

5.00 [1.00, 5.75]

0.738

< 0.001

B1 score: number of episodes before/off treatment*

0.256

0.495

 4 or more episodes

99 (77.3)

36 (85.7)

 2 or 3 episodes

20 (15.6)

5 (11.9)

 1 episode

9 (7.0)

1 (2.4)

B2 score: frequency of episodes before/off treatment*

0.433

0.085

 Average to high, including rapid cycling

91 (71.1)

37 (88.1)

 Low, spontaneous remissions of 3 or more years

28 (21.9)

4 (9.5)

 1 episode only, risk not known

9 (7.0)

1 (2.4)

B3 score: duration of the treatment

0.470

0.018

 2 or more years

90 (70.3)

23 (56.1)

a

 1–2 years

24 (18.8)

6 (14.6)

 Less than 1 year

14 (10.9)

12 (29.3)

a

B4 score: compliance during period(s) of stability*

0.503

0.063

 Excellent, e.g., documented by drug levels

106 (83.5)

40 (97.6)

 Good, more than 80% levels in the therapeutic range

16 (12.6)

1 (2.4)

 Poor, repeatedly off treatment

5 (3.9)

0 (0.0)

B5 score: use of additional medication during the period(s) of stability*

0.507

0.043

 None except infrequent sleep medications

14 (10.9)

2 (4.9)

 Low-dose antidepressants or antipsychotics, or prolonged use of sleep medications

23 (18.0)

2 (4.9)

 Prolonged or systematic use of antidepressants or antipsychotics

91 (71.1)

37 (90.2)

 Total score

3.00 [1.00, 5.00]

0.50 [0.00, 3.75]

0.778

< 0.001

Lamotrigine treatment response

Lamotrigine responders*

8 (15.7)

3 (9.4)

0.192

0.517

A score (improvement)

5.00 [3.25, 8.00]

6.00 [3.00, 7.75]

0.037

0.880

B1 score: 2 or 3 episodes before/off treatment (vs. 4 or more)*

6 (11.8)

2 (5.9)

0.209

0.467

B2 score: low frequency of episodes (vs. average to high)*

5 (9.8)

2 (5.9)

0.146

0.697

B3 score: duration of the treatment*

0.245

0.550

 2 or more years

39 (76.5)

23 (67.6)

 1–2 years

6 (11.8)

7 (20.6)

 Less than 1 year

6 (11.8)

4 (11.8)

B4 score: compliance during period(s) of stability*

0.091

1.000

 Excellent, e.g., documented by drug levels

49 (96.1)

32 (94.1)

 Good, more than 80% levels in the therapeutic range

1 (2.0)

1 (2.9)

 Poor, repeatedly off treatment

1 (2.0)

1 (2.9)

B5 score: use of additional medication during the period(s) of stability*

0.223

0.589

 None except infrequent sleep medications

1 (2.0)

2 (5.9)

 Low-dose antidepressants or antipsychotics, or prolonged use of sleep medications

2 (4.0)

2 (5.9)

 Prolonged or systematic use of antidepressants or antipsychotics

47 (94.0)

30 (88.2)

Total score

3.50 [1.00, 5.00]

4.00 [0.00, 5.00]

0.067

0.648