BDNF and early-onset autosomal dominant Alzheimer disease: However, BDNF has been proposed as a broad biomarker of several neuropsychiatric disorders that are highly comorbid with AUD and/or cognitive impairment, especially depression [45], posttraumatic stress disorder [46], schizophrenia [47], cocaine use disorder [48,49], Parkinson’s disease [50] and Alzheimer’s disease [51].