Amyloid Deposits Not Associated With Depression in Seniors

A study in Biological Psychiatry found that abnormal amyloid (Aß) deposits were evident in fewer older adults with major depression compared to non-depressed controls, reports EurekAlert . "This insight is important, because tests — like the positron emission tomography (PET) scans that enable detection of deposited amyloid — may someday play a role in helping doctors to make this distinction," said Biological Psychiatry editor John Krystal. The investigators examined 119 older adults with major depression and 119 non-depressed participants, average age 71. The researchers collected blood and DNA samples, and detected Aß deposits in their brains with PET scans. "Surprisingly, we did not observe evidence of increased amyloid deposition in the participants with major depression," said University of California, San Francisco Professor Scott Mackin. "Instead, we saw decreased amyloid deposition when we compared the groups in several different ways." Significant Aß deposits were identified in just 19 percent of participants with depression, versus 31 percent of controls. Subjects with depression met expectations by performing worse on cognitive and memory tests than non-depressed subjects, while those with brain Aß deposits performed worse on the memory tests, regardless of whether they were depressed or not.