According to the National Alliance on Mental Illness, depression affects more than 6.5 million of the 35 million Americans aged 65 years or older. Most of them have been experiencing episodes of depression throughout their lives. For others, depression has a first onset in late life—even persons in their 80s and 90s. However, those numbers—as well as the statistics on depression in the middle-aged–be much larger according to a new study from the Johns Hopkins Bloomberg School of Public Health. The study found that common methods of assessing mental or physical disorders may consistently underestimate the prevalence of mental disorders among middle-aged and older adults.
The analysis, led by postdoctoral fellow Dr. Yoichiro Takayanagi, and published in the January 8 online edition of JAMA Psychiatry, reveals substantial discrepancies among mid-life and late-life adults in reporting past mental health disorders, including depression, compared with physical disorders such as arthritis and hypertension.
The study found that the lifetime estimates of mental disorders ascertained by retrospective versus cumulative evaluations were 4.5% versus 13.1% for major depressive disorder; 0.6% versus 7.1% for obsessive-compulsive disorder, 2.5% versus 6.7% for panic disorder, 12.6% versus 25.3% for social phobia, 9.1% versus 25.9% for alcohol abuse or dependence, and 6.7% versus 17.6% for drug abuse or dependence.
In contrast, the estimates of physical disorders measured by retrospective versus cumulative evaluations were 18.2% versus 20.2% for diabetes, 48.4% versus 55.4% for hypertension, 45.8% versus 54.0% for arthritis, 5.5% versus 7.2% for stroke, and 8.4% versus 10.5% for cancer.
Dr. Mojtabai explained that the contrast between the recall of mental and physical disorders is noteworthy and may be attributable to differences in age at onset and the course of these disorders. “Stigma associated with mental disorders, as well as the fluctuating course of mental illnesses, might partly explain the discrepancies, as well as differences in ages of onset of mental and physical disorders. Mental disorders start earlier and have a higher prevalence in early to mid-life, whereas physical disorders are typically illnesses of middle and older age and tend to be chronic.”
Published originally on Sanity Break at Everyday Health.