Depression is the most common mental illness, yet we still do not fully understand what depression is. CAMH researchers are tackling the challenges of unravelling the biology of depression and improving treatments.
Depression — it may be what comes to mind first when we think of mental illness.
And it’s no wonder why. The federal government’s 2012 Canadian Community Health Survey – Mental Health found that about one in nine Canadians aged 15 and older – 11.3 per cent, or 3.2 million people – had experienced depression in their lifetime, and 4.7 per cent had depression in the previous year.
The first antidepressant medications became available in the 1950s, and talk therapies like cognitive behavioural therapy have also grown in use since then. Despite the success of these treatments for many people, they don’t help everyone. CAMH researchers describe the ongoing challenges and the directions they’re pursuing to overcome these challenges.
Beyond medications
“The antidepressant medications we have today were more or less chance discoveries from decades ago, and there have been no major improvements in drug development since then,” says Dr. Yuliya Nikolova, Scientist in CAMH’s Campbell Family Mental Health Research Institute. “These medications also don’t work for everyone.”
Depression is the leading cause of disability worldwide.
Up to 40 per cent of people with depression have hard-to-treat, or treatment-resistant depression, meaning they do not experience a noticeable improvement in their symptoms after trying at least two different antidepressant medications.
“That’s a huge gap,” says Dr. Jeff Daskalakis, Co-Director of the Temerty Centre for Therapeutic Brain Intervention and Chief of the Mood and Anxiety Division at CAMH. “The health-care costs associated with treatment-resistant depression are much higher than the costs to treat all other people with depression, because these individuals may experience suicidal thoughts, develop other illnesses or be off work for longer periods of time.”
“We need to find new ways to treat depression, including brain stimulation therapies and novel medications,” says Dr. Daskalakis. Evidence into brain stimulation for hard-to-treat depression is growing – most recently, CAMH researchers showed that a three-minute version of a brain stimulation treatment was as effective as the standard 37-minute version. And in drug development, CAMH researchers are investigating new molecules and novel ways of delivering these, including a nasal spray.
Another research goal is optimizing existing treatments. For example, a CAMH study using genetic testing is helping health-care professionals identify effective medications and doses for their patients based on the patient’s unique DNA.
Technology may also extend the reach of treatment. “Psychotherapy is effective, but people have trouble getting access,” says Dr. Daskalakis. In one initiative, CAMH researchers are studying whether an online mindfulness-based therapy, offered via smartphones and combined with personal health coaching phone calls, may be effective in treating youth with depression.
Understanding biology
While knowledge of the factors that contribute to depression – from social and environmental influences to biology — is expanding rapidly, there is much to uncover.
“We simply do not fully understand what depression is,” says Dr. Daskalakis.
“Another challenge is concurrent disorders — depression tends come with a host of other mental illnesses, as well as addictions,” says Dr. Lena Quilty, Scientist in the Campbell Institute and the Addictions Division at CAMH.
“In depression, and in mental illness in general, we’re still focused on a categorical system where disease is characterized by sets of symptoms, rather than the underlying biology,” says Dr. Etienne Sibille, Deputy Director and Senior Scientist in the Campbell Institute. “The major breakthrough will be when we understand the biological pathways and how these are shared across mental illness, and when we can target these.”
A promising opportunity comes from “big data” or neuroinformatics, enabling researchers to pool and analyze data from multiple sources. “There is so much information we can leverage now in a way that we’ve never been able to before, and it’s increasing by leaps and bounds, from traditional blood tests to wearable devices that can monitor health,” says Dr. Quilty.
As a touchstone for where we are today in understanding and treating depression, and where we can go, Dr. Sibille considers another major illness: cancer. “It’s the same as cancer 30 years ago. Initially, cancer was viewed as diseases of separate organs. Now, it’s seen as a disease of biological pathways, with the same pathway affecting different organs. Today, the first thing cancer doctors do is take a biopsy and a molecular analysis. From there, they can determine the pathway, and the pathway defines the appropriate treatment.”
“Cancer research and care show us that huge improvements in both understanding and treatment can occur. This provides a roadmap of where treating depression and other psychiatric disorders could be in a few years,” says Dr. Sibille.
In the Summer 2018 Issue of CAMH Discovers Quarterly:
