With the explosive surge in population, there are bound to be increases in problems. These problems range from mental issues and diseases. What has also influenced mental illness, is the technology age in which we live in. In modern society, the harder you work, the more robotic you become. Information is drilled into your brain at an early age in order to groom you to become a good worker. What is also drilled into your head, is the illusion of freedom. This education continues from childhood to college. In your off-time you are likely to be sucked into the trap of mass media, which also heavily influences the mind.
With this zombie like society, it is no wonder mental illness has run rampant.