Mental illness may be a sign of the times, a new study suggests.
"We have become a culture that focuses more on material things and less on relationships," said lead researcher Jean Twenge, author of "Generation Me" and an associate professor of psychology at San Diego State University. Twenge said this focus is affecting mental health on a societal level.
The study, which has not yet been officially published, analyzes data on the mental health and personality of over 63,000 high school and college students between 1938 and 2007.
Drawing on self-reports from widely used psychological surveys, including the Minnesota Multiphasic Personality Inventory, researchers found that over time, more and more students are reporting symptoms of mental illness.
Eight-five percent of college students today fall above the average mental illness "score" of students in the 1930s and 1940s.
Students today report they feel significantly more isolated, misunderstood, and emotionally sensitive or unstable than in decades past. Teens were also more likely to be narcissistic, have low self-control, and express feelings of worry, sadness, and dissatisfaction with life.
Although self-reported symptoms would not be enough to diagnose mental illness in these populations, the authors suggest that changes in students' responses over time suggest a real change in mental health levels.
The authors are also quick to point out that increases in these symptoms may even be underestimated in recent years because of the increasing number of Americans on antidepressant and anti-anxiety medication.
In more recent times, they write, "those answering the survey might have had their mental state stabilized already by drugs."
A study out of Northwestern University released Monday offers further support to this claim: researchers found that patients on the antidepressant drug Paxil experienced changes in personality, such as being more outgoing. As a possible result, they may have been less likely to suffer from psychological problems or relapse into depression.
Why are teens having more psychological issues with each passing generation?
One possibility put forth by the researchers is that levels of mental illness increase when the economy goes south. However, given that the economy has fluctuated considerably since the 1940s but this trend has only showed a steady increase, researchers say this is unlikely.
It is also possible that students today are more willing to admit to having psychological problems than generations past because of increasing awareness and acceptance of mental health issues.
But according to Twenge, the MMPI controls for this "socially desirable responding." The data do not suggest that the extent to which respondents adjust their responses to give the "right" impression has changed over time.
The most likely culprit, the authors write, is that changes in our cultural values are behind teens feeling more anxious, depressed, isolated, and stressed-out.
"When you talk about generational change -- as this study does -- it's really about changes in the culture," Twenge said.