Page 33 - JCBP-3-1

Journal of Clinical and
Basic Psychosomatics BDNF in psychotherapy

does not invalidate its value as an indicator of disease or could influence the findings, including those relating to
treatment response. However, it implies that blood BDNF disease pathogenesis, such as the role of childhood trauma
51
measures do not necessarily reflect mechanisms related to and other environmental or genetic risk factors. The
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central nervous system effects and therefore cannot be few positive reports of associations with psychotherapy
interpreted as such. may still present a view distorted by publication bias.
Although genetic investigation avoids these concerns, Nevertheless, strong circumstantial evidence supports the
no consistent association of the BDNF genotype with the role of BDNF in depressive and anxiety disorders as well
treatment response has been identified. The discrepancy as their treatment, warranting further studies to enhance
between studies is notable; the highly significant findings of the understanding of the mechanisms underlying their
Schosser et al. contrast strongly with the negative findings response to psychotherapeutic interventions. However, it
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would be premature to draw any clinical implications from
of other smaller studies of depression. No evidence on the this work.
role of a BDNF genotype in studies of psychotherapy for
anxiety disorders was apparent, despite one report of a Studies of blood BDNF do not, and perhaps cannot, yield
particularly large controlled investigation. 39 consistent results concerning psychotherapeutic response
for at least two reasons. First, serious methodological
How these findings compare with those from studies of
antidepressant or anxiolytic drug response may be relevant issues, particularly in studies of plasma, have rarely been
adequately considered. Second, peripheral blood BDNF
to understanding the therapeutic mechanisms.
is likely to have a strong contribution from peripheral
The BDNF polymorphism rs6265 (Val66Met), the organs, including the cardiovascular system and gut,
most studied variant, shows some consistency in findings which confounds the interpretation that changes in BDNF
indicating a significant effect on antidepressant efficacy, levels might reflect its activity in the brain. Any attempts to
with the Met allele associated with a better treatment further investigate the peripheral measurement of BDNF
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response. Most studies of peripheral blood BDNF need to be performed in well-designed studies that pay
levels report lower levels before antidepressant treatment more attention to these and other confounding factors.
than after. Different antidepressant drugs elevate serum/ Genetic association studies have the advantage of the
plasma BDNF, which are reportedly reduced in patients known relationships with some aspects of brain function
with depression. Furthermore, animal studies have and dysfunction, and their inherent nature indicates that
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shown that antidepressant medication increases BDNF any association is likely causal rather than consequential.
mRNA and BDNF protein levels in the cerebral cortex However, the evidence for the influence of BDNF SNPs
and hippocampus. Therefore, BDNF may mediate the on the psychotherapeutic response is inconsistent and
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effect of antidepressants in reversing depression-related very limited. Future work needs to consider interactions
neuronal dysfunction by promoting neurogenesis and with other known or likely influences, such as underlying
plasticity. An association between BDNF Val66Met and cognitive function and pathogenic risk factors.
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BDNF peripheral levels was also suggested, in which the
Met allele was associated with higher BDNF serum levels. 63 The lack of DNA methylation studies on BDNF in
response to talking therapies in the contexts of depression
4. Conclusion or anxiety is disappointing, especially given the rapid
In this review, we did not conduct meta-analyses of expansion of findings supporting the role of this epigenetic
the findings but critically assessed individual reports, factor in the control of BDNF expression and its influence
occasionally identifying major methodological concerns on various aspects of psychiatric disease and treatment.
that question research validity. In addition, we did not This area presents a significant opportunity for future
summarize and analyze all types of psychotherapies but research to determine the importance of BDNF changes in
focused on talking therapies such as CBT, interpersonal psychotherapy, despite the challenges in differentiating the
therapy, psychodynamic therapy, family therapy, and somatic and psychiatric correlates of such changes.
MBCT. Further limitations are shared with many of the Acknowledgments
reviewed reports. Consideration is not always given to
why the participants undergo psychotherapy rather than None.
pharmacotherapy. An important question is whether the
subjects are drug-naïve and at an early stage of their illness Funding
or have previously received drug treatment to which they This study was supported by the National Natural Science
have not responded adequately. This would differentiate the Foundation of China (No. 82371534 to Zhi Xu); the Open
two highly dissimilar cohorts. Many other variable factors Project Programme of the Key Base for Standardized

Volume 3 Issue 1 (2025) 27 doi: 10.36922/jcbp.4461