LCN2 and major depressive disorder: Thus, while a number of animal and human studies have found elevated levels of lipocalin in disease states such as depression [22, 40], schizophrenia [43], multiple sclerosis [20], Parkinson’s [31] and Alzheimer’s disease [29, 30], suggesting lipocalin overexpression might play an important role in mediating the observed deficits, other authors have reported findings such as increased anxiety- and depressive-like behavior and cognitive impairments displayed by LCN2-null mice [32, 33, 35, 44].