A recent study by San Diego State University psychology professor Jean Twenge looked at Minnesota Multiphasic Personality Inventory (MMPI) test results for high school and college students from 1938 through 2007. (The results will be published in a future issue of the Clinical Psychology Review.) The MMPI is one of, if not the, most popular personality tests, which measures (or claims to measure) people's mental health along ten different axes.
Twenge found that in 2007, five times as many people surpassed the threshold to be considered to have mental health issues as did in 1938. Especially high were the increases in hypomania and depression. And this doesn't even consider the vast numbers of people taking antidepressants and other meds that alleviate the symptoms the MMPI asks about.
Now, add to the fact that as a nation we're going crazy, the fact that we're exporting our model of mental health to the rest of the world. We've been aggressively preaching that "mental illnesses" should be considered a "brain disease", in the theory that this would help remove the stigma around them.
According to the research of Professor Sheila Mehta of Auburn University, though, this in not actually the result: considering mental illness as a neurological defect actually tends to make other people treat the sufferer less kindly. Mehta has actually studied how other people treat those they believe have a "brain disease", versus those who they believe have a psychosocial problem. She says, “Viewing those with mental disorders as diseased sets them apart and may lead to our perceiving them as physically distinct. Biochemical aberrations make them almost a different species.”
This may be why schizophrenics in the United States and Europe, where the "brain disease" idea holds sway, have a significantly higher relapse rate than those in other countries. More "primitive" notions of mental illness may actually help keep the troubled individual in the social group, and religious beliefs that attribute their problem to "evil spirits" or somesuch may allow for calmness and acquiescence and a less stressful response.