Many factors may be contributing to the rise. While young adulthood has long been recognized as a tumultuous time, greater awareness of mood and anxiety disorders and the availability of drugs to treat them have resulted in young people being diagnosed earlier, Spivack said.
Some young people are under a lot of stress, with more students working while going to school and under greater pressure to declare a major and career field as soon as possible, he said.
In addition, the onset of some disorders appears in the early adult years, just as young people are leaving the structured world of childhood and navigating their new freedoms and responsibilities.
"Years ago we thought that childhood and late adolescence are happy times and people didn't tend to be depressed," Olfson said. "In fact, it is in late adolescence and early adulthood some of these problems have their onset."
A limitation of the analysis is that it did not include eating disorders, said Dr. Harry Brandt, director for the Center for Eating Disorders at Sheppard Pratt and head of the psychiatry department at St. Joseph Medical Center.
At least half of the patients he sees at the eating disorder center are young adults, he said. "I was very surprised that among all the diagnoses, they did not look at eating disorders, since those are among the most deadly and serious disorders of that age range," he said.
In general, Brandt said, young people resist treatment because of denial and the societal stigma of mental illness.
Spivack said that Towson is trying to raise awareness of mental health problems and services. For instance, this semester, for the first time, resident assistants took part in a mandatory suicide-prevention training session.
"I think that we probably see about 10 percent of the student body in any given year," Spivack said. "We certainly are not catching all of them."
