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Cases of burnout have been increasing at an alarming rate in recent years among millennials and Gen Zers. It's a growing problem in today's workplace because of trends like rising workloads, limited staff and resources and long hours. It's no surprise, then, that a recent study by Mind Share Partners, Qualtrics and SAP reveals that half of millennials and 75% of Gen Zers have left a job for mental health reasons. The study, which looked at mental-health challenges and stigmas in the U.S. workplace, polled 1,500 respondents ages 16 and older working full-time. Another recent study, by the American Psychological Association, found the percentage of young adults experiencing certain types of mental health disorders has increased significantly in the past decade. In particular, the percentage of people dealing with suicidal thoughts increased 47 percent from 2008 to 2017. The Mind Share Partners, SAP, and Qualtrics study also shows that the younger generations suffer more from mental illnesses. Younger people dealt with a mental illness at about three times the rate of the general population. The findings are corroborated by another recent study, which shows that while the amount of serious psychological distress increased across most age groups, the largest increase between 2008 and 2017 was among adults ages 18–25, at 71%. For adults ages 20–21, the figure was 78%. For more on tech, transformation and the future of work, join CNBC at the @ Work: People + Machines Summit in San Francisco on Nov. 4. Leaders from Dropbox, SAS, McKinsey and more will teach us how to balance the needs of today with the possibilities of tomorrow, and the winning strategies to compete. A 2017 report from the Center for Collegiate Mental Health at Penn State University, meanwhile, found the number of students at various colleges and universities seeking mental health help increased five-fold from 2011 to 2016.

What's behind the rise

While there's no definitive cause of the trend, some researchers shared their thoughts with CNBC. Jean Twenge, author of iGen, a book about the effect technology has on this generation, says that "the rise of the smartphone and social media have at least something to do with it." Twenge said the general pattern is that teens and young adults are spending less time face-to-face with others and more time on their screens. "The pattern lines up very precisely that the majority of Americans owned a smartphone from the beginning of 2012 to 2013," she said. She noted that at that time, mental health issues began to spike. "Reading about a news event is not going to have the effect on your life and mental health as a fundamental shift in how you spend your time," she said. "And that's what's happened. Less time sleeping, less time on face-to-face interactions is not a formula for better mental health."

But Peter Gray, a research professor at Boston College, said that it's not social media or young people's fractured attention spans that are causing their anxiety; it is school itself. He traces a progression from the mid-1950s in which society has gradually taken away children's internal locus of control (someone with an internal locus of control is likely to believe that both successes and failures are due to their own efforts). As a result, many young people today are lost. "Since the mid-1950s, when they began taking away children's play, people haven't learned to take control of their own lives." Gray said that control is essential to ward off excessive anxiety. Gray advocates overhauling our educational system to instill more of that focus. He supports the Let Grow Kids Foundation and others. His advice for students is to take a year off between high school and college to check out careers they may be interested in. Whatever the cause, the statistic highlights several issues plaguing millennials, like a rise in depression and "deaths of despair" (death from drugs, alcohol and suicide), unaffordable living costs and burnout. Eighty-six percent of respondents in the Mind Share Partners, SAP, and Qualtrics study said a company's culture should support mental health. "Mental health is becoming the next frontier of diversity and inclusion, and employees want their companies to address it," the authors wrote.

Cisco confronts mental health in the workplace head-on

Roughly 1 in 5 adults in the U.S. per year suffer from mental illness, according to the National Alliance on Mental Illness. The costs to treat depression, stress, anxiety and other ailments exceeds $200 billion a year, and for many employers the number of sick days and lost productivity associated with mental health represent one of their biggest expenses. The extent of the problem has caught some off guard. Fran Katsoudas, chief people officer at Cisco, recalled that after the deaths of celebrities Anthony Bourdain and Kate Spade last year, the company's CEO, Chuck Robbins, sent out a company-wide email addressing the issues of mental health and suicide. In it he wrote: "In light of recent tragedies, I wanted to step away from Cisco Live for a moment to talk about the importance of mental health. Unfortunately, we all know friends, family, and coworkers battling mental health conditions, or maybe you're going through your own struggles." Robbins, who took over the CEO role in 2015, encouraged employees to "talk openly and extend compassion" and asked that they "have each other's backs." Katsoudas said the response from Robbins' email was unlike anything the company had ever seen before. "This was a conversation that our employees wanted to have — and not only the conversation, but they needed support."

Cisco is optimistic about the opportunity to drive culture change and create an environment where mental health is viewed, spoken about and supported in the same way as physical health. Cisco spokesperson