According to new research conducted in the United Kingdom, the rates of common mental disorder (including depression and anxiety) have not increased in recent years—contradicting many anecdotal concerns that the prevalence of mental disorder is on the rise.
The study, published in the June issue of the British Journal of Psychiatry, was carried out by researchers from the University of Leicester, UCL (University College London) and King's College London,
Researchers used data from three British Adult Psychiatric Morbidity Surveys, carried out in 1993, 2000 and 2007, to monitor changes in the rates of mental health disorders in England over the 15 year period. There were 8,670 survey participants in 1993, 6,977 participants in 2000 and 6,815 participants in 2007.
The researchers found almost no change in the rate of common mental disorder across the 15-year period for women. It affected 18.1 percent of women in 1993, 18.5 percent in 2000 and 18.9 percent in 2007. However in men, the rate of common mental health disorder was slightly higher in 2000 (12.6 percent) than in 1993 (10.9 percent) or 2007 (11.8 percent).
The researchers did identify an increase in sleep problems among women over the 15-year period. In 1993, sleep problems affected 28.4 percent of women, rising to 34.7 percent in 2000 and 36.7 percent in 2007. But there was no clear increase for other symptoms such as irritability, worry or fatigue among women or men.
The study participants were divided into nine birth cohorts, which also allowed the researchers to analyse data for each cohort as they aged across the 15-year period.
Researchers found that men in the cohort born in 1950-1956 had higher rates of common mental disorder than men born in the previous cohort of 1943-1949, by around one-third. But after this, the rates of common mental disorder in subsequent cohorts remained stable.
They believe this may be due to changes in society and people's lifestyles at that time.
"We found that men born in 1950-1956 were the first birth cohort to experience higher rates of disorder," explained Prof. Terry Brugha, professor of psychiatry at the University of Leicester.
"These men were towards the beginning of the baby-boom generation and were teenagers during the 1960s," he added. "They were among the first to experience teenage culture, both home grown and imported from the USA, including greater exposure to harmful substances."
This, according to Brugha, may have made their transition to adulthood "different to that of previous generations."
Researchers found more mixed trends among women. Again, those born in 1950-1956 had a slightly higher prevalence of common neurotic disorder, sleep problems and worry than those born in the 1943-1949 cohort. However, the difference between the two age groups was less pronounced than among the men.
Professor Brugha concluded: "Overall, we found little evidence that the prevalence of common mental disorder, which includes depression and anxiety disorders, is increasing in England. Our finding of stable rates contradicts popular media stories of a relentlessly rising tide of mental illness."
Spiers N, Bebbington P, McManus S, Brugha TS, Jenkins R and Meltzer H. Age and birth cohort differences in the prevalence of common mental disorder in England: the National Psychiatric Morbidity Surveys, 1993-2007. British Journal of Psychiatry 2011; 198: 479-484