Table 2 Statistics on within-group meta-analyses regarding peripheral brain-derived neurotrophic factor levels in bipolar disorder

Within-Group

N of pairwise

Number of subjects

Hedges’ g

P value

I ²

Q

P value

Mania

 Mania– all*

13

556

0.26

0.09

0.45

0.003

69.69

39.60

0.001

 Serum and plasma*

12

454

0.30

0.08

0.44

0.005

78.48

18.59

0.001

 Serum

5

122

0.39

−0.03

0.81

0.065

78.48

18.59

0.001

Plasma*

7

332

0.23

0.02

0.44

0.028

55.20

13.39

0.037

 Whole blood

1

102

0.01

−0.19

0.20

0.941

N/A

N/A

N/A

 Depression

 Depression – all

8

184

0.05

−0.28

0.38

0.747

76.51

29.79

0.001

 Depression – except Mackin 2007 [71]

7

164

0.15

−0.18

0.49

0.364

72.84

22.09

0.001

 Serum

5

88

−0.12

−0.52

0.29

0.563

72.15

14.36

0.006

 Plasma

3

96

0.40

−0.40

1.21

0.329

85.93

14.22

0.001

 Response

3

115

−0.06

−0.24

0.18

0.492

N/A

N/A

N/A

 Non-response

5

69

0.13

−0.53

0.79

0.702

85.69

1.51

0.001

Moderators within-group

N of pairwise

Number of subjects

Slope

P value

Intercept

Z

P value

Mania

 Age of BD Patients – all

9

456

−0.01

−0.04

0.02

0.398

0.80

1.39

0.165

 % Females – all

13

556

0.01

−0.03

0.02

0.478

0.07

0.27

0.782

 Baseline YMRS scores

12

542

0.01

−0.01

0.02

0.930

0.20

0.63

0.522

 Difference in YMRS_{(After – Before)}

12

542

−0.01

−0.02

0.02

0.298

0.16

1.42

0.155

 % Change in YMRS Scores

12

542

−0.01

−0.02

0.01

0.213

0.77

1.73

0.083

 Follow-up duration (weeks)

13

556

0.01

−0.01

0.03

0.396

0.19

1.63

0.101

 Year of publication

13

556

−0.07

−0.12

−0.01

0.011

141.63

2.53

0.011

Depression

 Age of BD patients – all

6

164

−0.01

−0.05

0.02

0.393

0.50

0.69

0.489

 % Females – all*

6

164

0.01

0.00

0.02

0.042

−0.54

−2.29

0.021

 % Females – excluding Mackin 2007 [71]

5

144

0.01

−0.01

0.01

0.555

−0.20

−0.68

0.490

 Baseline HDRS scores

8

184

0.02

−0.18

0.22

0.823

−0.42

−0.19

0.845

 Difference in HDRS_{(After – Before)}

7

164

−0.02

−0.09

0.06

0.658

−0.01

−0.01

0.988

 % Change in HDRS scores

7

164

0.01

−0.01

0.02

0.566

−0.05

−0.13

0.892

 Follow-up duration (weeks)

8

184

0.01

−0.05

0.07

0.673

−0.04

−0.12

0.899

 Year of publication

8

184

0.01

−0.11

0.11

0.987

−1.76

−0.01

0.988