TABLE 3.
Correlations between BDNF levels and cognition.
| Study | Diagnosis | BDNF type | Cognition measurement | Correlation measure | Correlation coefficient |
| Asevedo et al. (59) | SZ | Serum | Semantic generation task | Spearman’s correlation | 0.38* |
| Letter memory task | −0.45* | ||||
|
| |||||
| Carlino et al. (42) | CH-SZ | Serum | TMT Part B | Partial correlation | 0.55*** (low truncated BDNF) |
| Digit symbol coding | 0.36* (low truncated BDNF) | ||||
| Digit span forward | 0.36* (low truncated BDNF) | ||||
|
| |||||
| Chou et al. (49) | EU-BD | Plasma | Sounds RT (divided attention) | Partial correlation | Data missing* |
| Faces 2 true positive (faces memory) | Data missing** | ||||
|
| |||||
| Dias et al. (52) | EU-BD | Serum | Test of verbal fluency (COWAT) | Pearson’s correlation | 0.26* |
|
| |||||
| Dong et al. (64) | SZ | Serum | RBANS total score | Pearson’s correlation | 0.18** (CLZ, M) |
| 0.39** (RISP, M) | |||||
| 0.30** (TYP, M) | |||||
| 0.55* (TYP, F) | |||||
|
| |||||
| Hori et al. (46) | CH-SZ | Serum | Card block 61–80 (IGT) | Pearson’s correlation | 0.23* |
| Card block 81–100 (IGT) | 0.27* | ||||
|
| |||||
| Hori et al. (60) | SZ | Serum | Verbal memory (BACS) | Pearson’s and Spearman’s correlation | 0.19* |
| Attention and processing speed (BACS) | 0.16* | ||||
|
| |||||
| Li et al. (70) | SZ | Serum | RBANS total score | Pearson’s correlation | 0.33*** (without T2DM) |
|
| |||||
| Niitsu et al. (61) | SZ | Serum | Information subscale (WAIS-R) | Spearman’s correlation | 0.29* |
|
| |||||
| Wei et al. (44) | CH-SZ | Serum | VFT total score | Partial correlation | 0.33* |
|
| |||||
| Wu et al. (45) | CH-SZ | Serum | RBANS total score | Pearson’s correlation | −0.38* (TD) |
| Immediate memory index (RBANS) | 0.32* (WTD) −0.36* (TD) |
||||
| Delayed memory index (RBANS) | −0.38* (TD) | ||||
|
| |||||
| Wu et al. (38) | DN-FEP-SZ | Serum | Delayed memory index (RBANS) | Pearson’s correlation | −0.26* (high−BDNF) |
|
| |||||
| Xiao et al. (41) | DN-FEP-SZ | Serum | TMT Part B | Spearman’s correlation | −0.40** |
| VFT-animals | 0.27* | ||||
|
| |||||
| Xiu et al. (39) | SZ | Serum | VFT total score | Partial correlation | 0.30* |
| WCST sub-score | −0.27* | ||||
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| |||||
| Yang et al. (40) | SZ | Plasma | Learning and memory (MCCB) | Pearson’s correlation | 0.28* |
|
| |||||
| Zhang et al. (69) | SZ | Serum | RBANS total score | Pearson’s correlation | 0.21* |
|
| |||||
| Zhang et al. (48) | CH-SZ | Serum | Immediate memory index (RBANS) | Pearson’s correlation | 0.23*** |
|
| |||||
| Zhang et al. (47) | CH-SZ | Serum | RBANS total score | Pearson’s correlation | 0.34** (F) |
| Immediate memory index (RBANS) | 0.51*** (F) | ||||
|
| |||||
| Zhang et al. (58) | AC-SZ | Plasma | RBANS total score | Spearman’s correlation | 0.28* |
| Attention index (RBANS) | 0.27* | ||||
p-Value: *<0.05, **<0.01, ***<0.001.
AC, acute; BACS, Brief Assessment of Cognition in Schizophrenia; BD, bipolar disorder; BDNF, brain-derived neurotrophic factor; CH, chronic; CLZ, clozapine; COWAT, Controlled Oral Word Association Test; DN, drug naïve; F, female; FEP, first episode; EU, euthymic; IGT, Iowa Gambling Task; M, male; MCCB, MATRICS Consensus Cognitive Battery; RBANS, Repeatable Battery for the Assessment of Neuropsychological Status; RISP, risperidone; SZ, schizophrenia; TD, tardive dyskinesia; TMT, Trail Making Test; TYP, typical; VFT, Verbal Fluency Test; WAIS-R, Wechsler Adult Intelligence Scale Revised; WCST, Wisconsin Card Sorting Test; WTD, without tardive dyskinesia.