MAPT and major depressive disorder: An investigation comparing 2‐(1‐{6‐[(2‐[18F]fluoroethyl) (methyl)amino]‐2‐naphthyl}ylidene)malononitrile ([18F]FDDNP) protein binding in elderly individuals with late‐life depression without evidence of cognitive decline found that [18F]FDDNP aggregated protein binding in the anterior cingulate cortex was significantly related to apathy, but not depression, further implicating Aβ and tau in apathy.115