For example, observations from preclinical studies indicate the interest of serum BDNF as a promising biomarker for vulnerability to depression associated with epilepsy (Becker et al., 2015); yet, translation to clinical practice is likely to be hampered by the fact that serum BDNF measurement in patients has proven to be heavily influenced by presence of anti-seizure medications (McGonigal et al., 2023). This evidence concerns the gene BDNF and depressive disorder.