I think the research is self-fullfilling. Software engineers, Executive and Administrative Assistants, clerk typists, travel agents, financial sector workers and more have always spent 8 to 10 hours a day, predominately in front of their screens at work – long before cellphones and tablets, etc. The depression is more likely coming from the crushing corporate environment – and the corporate abusers want us to think it's something we're doing to ourselves with "screen time." The cellphones and tablets just became a self-treating distraction from the real root causes of our national malaise.