Finding new ways to treat late-life depression

Featured in CAMH Discovers, Spring 2019 Edition

Late life is full of transitions, such as retirement and physical changes. For some people, these changes can cause stress that can lead to developing late-life depression.

Finding effective ways to treat depression among older people is critical, because depression may pose added risks at this stage of life, including a greater risk of developing dementia. 

CAMH researchers are conducting a number of large-scale studies to identify new treatment approaches, and understand the link between late-life depression and dementia. CAMH is “at the forefront in terms of leading research in treating late-life depression and preventing its consequences,” says Dr. Daniel Blumberger, Head of the Late-Life Mood Disorders Clinic and Co-Director of the Temerty Centre for Therapeutic Brain Intervention at CAMH.

Challenges and risks

Depression in late life can often go undiagnosed or untreated by general medicine physicians due to the complex and overlapping symptoms with other medical conditions, says Dr. Blumberger. About five per cent of adults aged 60 and older experience a major depression, but depressive symptoms can be much more common, occurring in 10 to 15 per cent of older people. And the mental illness can have major impacts, including reducing an older person’s ability to function independently.

“Recurring or long-lasting depression in older people is a significant illness,” says Dr. Benoit Mulsant, Clinician Scientist in CAMH’s Campbell Family Mental Health Research Institute. “It decreases your life expectancy, because it can cause a person to develop poor nutrition habits, poor sleep and a lack of exercise; all those things are extremely unpleasant when you’re 40, and they’re deadly when you’re 80.” 

Another concern is “there is a very strong link between dementia and late-life depression,” says Dr. Mulsant. If left untreated, late-life depression is a risk factor for developing dementia. “It’s one of the major reasons to treat depression aggressively,” says Dr. Blumberger. 

At every age, depression may be associated with thoughts of suicide. Older people have a high risk of suicide, particularly among males. 

Still, says Dr. Blumberger, “when recognized and treated, depression in older adults can have very good outcomes.” Finding new treatments for those who do not respond to existing options is the challenge that CAMH researchers are seeking to address.

“It is more challenging to study older adults, as they often have co-occurring medical conditions,” explains Dr. Blumberger. “So there is frequently less data available on new and emerging treatments. That is why it is essential to support and encourage the study of novel treatments in older adults.”

Investigating new treatments 

One novel treatment in a CAMH study is a newer form of brain stimulation therapy, called theta burst stimulation (TBS), in older adults with depression. A recent CAMH study among younger adults showed that the newer, much shorter TBS treatment was just as effective as the standard version for hard-to-treat depression, referring to people whose depression has not improved after medication or talk therapy. The current study in older adults is supported by the Canadian Institutes of Health Research.

CAMH is one of five centres in North America involved in the OPTIMUM study, supported by the Patient-Centered Outcomes Research Institute in the U.S. The large-scale study is aiming to identify the optimal medication approach for older adults with hard-to-treat depression. The randomized trial is evaluating more complex medication strategies. In the Ontario arm of the study, led by Dr. Mulsant, 300 people aged 60 or over will receive one of three treatment strategies. 

“We’re looking at the outcomes and the side-effects of the different treatments,” says Dr. Blumberger, a co-investigator. “It’s a very important study that will influence how people end up prescribing these medications to older adults.”

Alongside the OPTIMUM trial, two studies funded by the U.S. National Institutes of Health are looking at links between late-life depression and dementia. One is a brain imaging study that aims to detect biological risk factors for developing dementia among older people with hard-to-treat depression, and older people who are responding to treatment. Another study is exploring the use of a blood test to identify who is at high risk of developing dementia.

The multiyear PACt-MD study is the largest Canadian clinical trial on dementia prevention, funded by Brain Canada and the Chagnon family. By combining brain stimulation and brain training exercises, the study’s goal is prevent decline in brain function that increases risk for developing dementia. CAMH is leading the study, in collaboration with four other leading research hospitals in Toronto: Baycrest, St. Michael’s, Sunnybrook and University Health Network (UHN). 

Triggers for late-life depression

One of the most common triggers for late-life depression is stress brought on from varying changes happening in late life. The transition from being very engaged in work to not working or retirement can be one of those stressors.

Another stressor is grief; as we get older, the feeling of loss can become overwhelming as we cope with the death of friends, a partner or parents. “It’s normal to grieve and mourn the loss of someone, but, for some people, that can trigger a major depression in their later years,” says Dr. Daniel Blumberger.

But Dr. Blumberger cautions against the idea that developing depression in late life is a normal part of aging. “I think there’s a stigma associated with aging that, as you get older, it is normal to be depressed because getting older is depressing, when in fact that’s not the case. That’s a belief that’s based in ageism. There are benefits and advantages of being older; it’s just a different phase of life.”

Dr. Benoit Mulsant says that although a person’s satisfaction in life decreases from their teen years until the age of 50, there is a positive turning point that has benefits into late life. “At age 50, your contentment increases. There are challenges, of course, like health problems and bereavement, but you also have wisdom, and have been through experiences of stress and trauma, so you, by definition, are a survivor, and that is a positive,” says Dr. Mulsant.