Although multiple sclerosis, neurodegenerative dementia, stroke, amyotrophic lateral sclerosis (Khalil et al., 2018), orthostatic hypotension (Park et al., 2021), hearing disorder (Park et al., 2016; Han et al., 2018), depression and anxiety disorders (Tauil et al., 2021), diabetes (Thota et al., 2022), psoriasis (Nowowiejska et al., 2022), transient ischemic attack (TIA; De Marchis et al., 2018) and sleep disorder (Jennum et al., 2017; Lysen et al., 2020; Targa et al., 2021) might impact NfL levels, we still found consistent results after adjusting for medical comorbidities. This evidence concerns the gene NEFL and major depressive disorder.