Later life depression offers clues in search for new therapies

Scientists have found an important clue in the quest to understand why people who suffer from depression in later life are harder to treat and keep well in the long term.

A study led by Baycrest Centre for Geriatric Care in Toronto, Canada, has found that older adults with depression don’t respond normally to emotional stimuli, such as when they see happy, sad or neutral faces.

The study appears online in the American Journal of Geriatric Psychiatry and is likely the first published data to focus specifically on emotional processing in un-medicated older adults with late-life depression.

“In our study we found significant differences between older depressed subjects and older healthy subjects in how they emotionally respond to and perceive facial expressions,” said principal investigator, Dr Linda Mah, a clinician-scientist in the Mood Clinic at Baycrest.

“Our data suggests that we need to also focus on emotion to better understand the neurobiology of late-life depression, so we can treat it more effectively and help people feel better longer,” said Dr Mah.

The study found that healthy controls were 16% slower in making judgments about physical features of the faces with positive or negative emotional expressions (happy, sad, fearful) relative to neutral faces – an indication that they were distracted or affected by the emotional expressions on faces.

The depressed participants showed no differences in response time to rating physical aspects of faces with emotional expressions or neutral faces. This suggests they were less sensitive to the effects of positive or negative emotional expressions.

Depressed participants had greater than 60% more difficulty with correctly labeling neutral faces, compared to healthy subjects. Depressed participants misread neutral expressions as happy, sad or fearful.

Dr Mah noted that an impaired ability to read other people’s emotional expressions can have social consequences and affect the quality of social interactions with others.

She also pointed out that these abnormalities in emotional processing seen in older depressed adults are distinct from those already reported in younger depressed adults who tend to perceive and process emotional stimuli more negatively overall when compared to healthy subjects. 

In separate research, approximately 44% of seniors in Canada who live in residential care homes are diagnosed with or have symptoms of depression, according to a new CIHI (Canadian Institute for Health Information) study, Depression Among Seniors in Residential Care .

The study found that 26% of seniors living in a residential care facility were diagnosed with depression, an additional 18% had depression symptoms with no documented diagnosis.