It is one of the most important and heart-breaking questions in all of health care: why do some young people with mental health challenges go on to develop life-threatening psychosis while others do not? We know from previous research that 75 per cent of youths who go on to develop psychosis had sought mental health treatment in the previous three years. But only 5 per cent of them showed any overt symptoms of psychosis before it emerged. Are there signs and symptoms that can be detected early enough, if we only knew what they were, that would make possible targeted treatments that might prevent psychosis from emerging?
Those are some of the fundamental questions that CAMH’s Toronto Adolescent & Youth (TAY) Cohort Study, which will follow 3,000 youth between the ages of 11 and 24 who have sought mental health treatment at CAMH, is trying to answer. The study will follow these young patients over a five-year period in unprecedented detail, tracking not just their clinical care inside and outside of CAMH, but also their genetics, brain circuitry and key aspects of brain functioning like memory and cognition.
“The brain changes rapidly as it is developing in adolescence and there are specific periods of time during spurts of growth and circuit formation when, if the brain is not developing normally, symptoms of mental illness can emerge,” says principle Investigator Dr. Aristotle Voineskos, Vice President, Research at CAMH and Director of the Campbell Family Mental Health Research Institute. “It’s not going to be possible to prevent psychosis in everyone, but if we can identify who the kids at higher risk are, we can design a system for them that is much more monitoring-intensive that may be able to prevent psychosis from emerging in some patients.”
Psychosis typically emerges in the late teens or early 20s and is the number one cause of disability for young people from 15 to 19.
“This is around the age of onset for most mental health and substance use difficulties so it’s a critical priority for research,” says Dr. Lena Quilty, Senior Scientist and Director of Research Training at CAMH, Senior Scientist at the Campbell Family Mental Health Research Institute and co-lead of the cognition and memory part of the study. “We have the capacity at CAMH now to do something of this size that isn’t being done anywhere else in Canada. The way it brings together experts from across the fields of mental health research is really exciting.”
As a world-class research facility embedded in a world-class hospital, CAMH was already uniquely positioned to take on a project of this size and it has been carefully thought out in a way that is perfectly aligned with CAMH’s core values and strategic vision, including making patients and families an integral part of all aspects of the process, and always staying focused on the direct impact CAMH research can have on patient care.
“This is not research that will go on for ten years and then we’ll sit down and think about how it can inform clinical practice.” says Senior Scientist Kristin Cleverley, who is the co-lead of the signs and symptoms section of the study. “Every time we make a decision about the study, we take it back to the clinical team and say ‘How exactly will you use this? Can we make a dashboard that you can immediately use to inform patient care?”
“We want to be better at predicting psychosis, just like we want to be better at predicting heart attacks, diabetes or MS,” says Cleverley. “It’s a puzzle. There are all these nuanced signs and symptoms and developmental and life events and to solve that puzzle we are bringing together all these different disciplines, including data scientists, neuroscientists, neurobiologists and developmental psychologists. We all have our areas of expertise and the nice thing is that we are all bringing our unique perspectives with a common goal.”
“We don’t take a diagnosis of this kind lightly. We have important frameworks for identifying people who are at high-risk for psychosis, but we are missing a huge proportion of the population that actually goes on to develop it,” says Dr. George Foussias, Chief of the Schiziphrenia Division at CAMH and Director of the Slaight Family Centre for Youth in Transition. “We know from previous research that there is an increased risk for psychosis in the future for young people who present early with mental health issues. But up until now we have not had a mechanism to predict who is at particularly high risk and needs more comprehensive services wrapped around them that are focused not just on their struggles in the moment, but also preventative interventions to try and minimize the risk that they will develop psychosis in the future. That is one of the big aims of the TAY cohort study.”
Four reasons why this study is truly unique
There are a number of factors that make the TAY Cohort study truly unique.
All 3,000 study participants are young Canadians who have already sought professional help for mental illness, meaning all of them are potentially at-risk for developing psychosis while they are being monitored closely in CAMH’s “living lab” over a five-year period.
The study will not focus on any one mental illness, as most studies typically do, but on all forms of mental illness.
The study will combine 5 years of direct clinical observation of signs and symptoms with data from brain imaging, genetics and cognitive function testing that will allow the team to create multi-dimensional trajectories for each study participant and look for similarities and patterns in groups of individuals.
For reasons that never made sense clinically, youth and adult mental health have been essentially treated as separate and distinct areas of research. By recruiting participants from the ages of 11 to 24, the study will be able to map out the full mental health trajectories of treatment-seeking youth as they transition to adulthood.“We want to understand how kids are moving through the system,” says Cleverley. “That’s rare in a large study like this.”
“Until now there hasn’t been a lot of attention paid to the evolution of psychosis and how it crosses boundaries longitudinally,” says Dr. Voineskos. “Different disorders develop at different times. A three-year-old doesn’t get psychosis, they get autism. A six-year-old gets ADHD or facial ticks. We know from studying adults that psychosis and depression overlap, but that’s a snapshot in time after the brain has fully developed. What if you could prevent that ADHD from turning into depression when they become a teenager? What if you could prevent psychosis by treating a totally different disorder earlier on?”
“The hope is that this study will help us support early intervention before the impact of these illnesses multiply,” says Quilty. “In terms of our ability to identify predictors it’s not just about psychosis. You can say the same thing about suicide risk. We know suicidal thoughts are not always linked to suicidal actions, so being able to identify those that are will help us intervene there as well. There are so many critical care outcomes that this study is going to inform, nor just psychosis.”
How this study will impact all future research at CAMH
Because all of this patient data will be entered into the CAMH Brainhealth Databank, it will benefit all future research at CAMH. For example, CAMH is on the leading-edge of research into the interaction between cannabis and the brain at a genetic and molecular level in regards to psychosis risk. While the science is still in its infancy, there are emerging concerns that cannabis-use among youth already at-risk for psychosis might increase that risk. If the mountain of patient data from at-risk youth in the TAY study finds more direct evidence of a link between cannabis and psychosis, it could have major implications for treatment and even public policy. The current national guidelines for lower risk cannabis use, developed by CAMH when cannabis was legalized, do recommend that teenagers avoid cannabis use and that anyone with a family history of psychosis abstain, but there are a growing number of scientists who believe that cannabis should not be used by anyone until the age of 25 when the brain has fully developed.
Another virtue of the study is that it is being used as a real-world training, education and mentoring exercise for dozens of post-grad students and early-career researchers and clinicians who have been recruited to assist in the massive logistics of the study.
“In addition to allowing so many patients to benefit from this research, It is also an unprecedented opportunity to build CAMH’s international impact by helping to train the next generation of leaders in child and youth mental health,” says Dr. Quilty.
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