Depression in later life may be an early warning from the brain, appearing years before Alzheimer’s begins to affect memory and thinking

A new study in JNeurosci found that faster accumulation of tau, a protein closely tied to Alzheimer’s, was associated with worsening depressive symptoms in older adults who remained cognitively healthy. Teodora Markova of Brandeis University and her colleagues investigated whether changes in mood might track the gradual buildup of tau in the aging brain.

Tau normally helps support the internal structure of neurons. When it becomes abnormal, however, it can collect into tangles that interfere with brain function. These tangles are one of the defining biological features of Alzheimer’s disease, alongside deposits of amyloid beta.