Credit – Otsuka Precision Health
Until recently, clinical depression treatments have fallen into just two categories: psychotherapy and antidepressant medications. But this year, the U.S. Food and Drug Administration cleared the first app-based treatment for major depressive disorder, which just became available for use this summer.
The app, called Rejoyn, is cleared as a supplement to currently approved therapies and works by using specifically designed tasks on a smartphone app to rewire neural signals. The idea is to tap into the brain’s circuits so depressive signals and pathways don’t spiral into the debilitating emotional episodes typical of clinical depression.
The evolution of a depression app
Dr. Dennis Charney, now dean of the Icahn School of Medicine at Mount Sinai, first got the idea for Rejoyn when studying prisoners of war years ago. He and his colleagues were focused on learning about resilience and what makes certain people better than others at coping with tragedy. The researchers interviewed about 30 Vietnam veterans, most of whom had survived years of torture and solitary confinement. “A number of them started telling us that when they were in solitary and all they could do was think, that their cognitive capacities increased dramatically,” says Charney.
That’s a well-known phenomenon in brain science called neuroplasticity: the ability of the brain to improve and reinforce certain circuits with practice. Some of the prisoners developed an ability to multiply 12 numbers at a time, while others wrote books in their mind that they eventually published. Another designed an entire house that he built after his release. These “exercises” allowed the prisoners to refocus their intellectual, emotional, and cognitive energy on something other than their challenging conditions, and essentially move beyond them.
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If these men were able to strengthen cognitive circuits in their brain under such horribly limited circumstances, Charney says he and his team wondered whether it would also be possible to “correct the abnormal circuits involved in depression” using similar tasks.
Years of research—which eventually led to Rejoyn—fine-tuned the tasks that people could easily do on their phone. What seems to work is a task that “does not remind people of past personal experiences, and is not related specifically to what is causing someone’s depression,” says Charney. It focuses more broadly on the depression circuit in the brain that links the prefrontal cortex, which is involved in memory, and the subcortical regions including the amygdala and hippocampus, which are tied to emotions associated with depression. In people with depression, imaging studies have shown that the memory and intellectual circuits are less active while the emotional signals are overactive, and that imbalance likely contributes to the negativity and hopelessness that are hallmarks of depression.
Inspired by a paper in 2008 that described how a computerized brain training program could improve working memory, Charney challenged one his mentees at the time, Brian Iacoviello, to develop a training exercise that might target key nodes in the brain’s neural networks that would have antidepressant effects.“We thought about targeting that imbalance and came up with a relatively straightforward, elegant, simple approach to activate both regions simultaneously through a computerized brain exercise,” says Iacoviello, now an adjunct assistant professor in the psychiatry department at Mount Sinai and a co-developer of Rejoyn. By doing so, they hoped to restore the balance between the circuits and return them to equal footing. “And maybe that would drive some antidepressant effect.”
The (shockingly simple) digital treatment
The task itself displays real faces showing different emotions—sad, happy, disgusted, angry, surprised—that users are asked to remember. The first level asks them to remember the emotion depicted in the previous face, and to answer yes or no about whether the current face they see on their screen matches that emotion. The next level asks people to remember the emotion they saw that was two faces prior to the current one. Because the faces depict emotions, the amygdala is activated—and asking people to remember these emotions stimulates the prefrontal cortex at the same time.