CDC Statistics: Mental Illness in the US

The U.S. Centers for Disease Control and Prevention (CDC) released a summary report yesterday detailing how the CDC measures mental illness in the U.S., and summary statistics from those measurements. Most of the information summarized in the report is not new, since it was previously published. What the report does do is bring a great deal of this information together in a single paper.

The report notes that according to the World Health Organization, mental illness — that is, any mental disorder — accounts for more disability in developed countries than any other group of illnesses, including cancer and heart disease. Yet all we hear people talk about in the media time and time again is reducing your risk of these health problems. We rarely hear anyone talk about reducing your risk of anxiety or depression.

According to a rigorous health survey conducted by the CDC in 2004, an estimated 25 percent of adults in the U.S. reported having a mental illness in the previous year. Lifetime prevalence rates of mental illness in the U.S. were around 50 percent when measured back in 2004. That means in a family of four, one of you likely has a mental illness.

However, mental illness is greatly weighted toward our senior years, when things start looking pretty bleak.

One of the surveys CDC researchers regularly collect data from is the National Nursing Home Survey, which surveys residents and staff members of nursing homes continuously throughout the year, every year. It’s not good:

The prevalence of nursing home residents with a primary diagnosis of mental illness in 2004 increased with age, ranging from 18.7% among those aged 65-74 years to 23.5% among those aged 85 years or older.

Dementia and Alzheimer disease were the most common primary diagnoses among nursing home residents with a primary diagnosis of mental illness, and the prevalence of each increased with age. Among nursing home residents with any diagnosis of mental illness (among any of 16 current diagnoses), mood disorders and dementia were the most common diagnoses among residents aged 65-74 years and 75-84 years.

Among residents aged 85 years or older, dementia (41.0%) was the most common mental illness, followed by mood disorders (35.3%). In 2004, approximately two thirds of nursing home residents had a diagnosis of a mental illness, and approximately one third of these had a mood disorder.

Two-thirds of people in nursing homes have a mental illness. It’s no wonder doctors prescribe so many medications to try and help stave off depression (nothing cures dementia, unfortunately). These are depressing numbers.

Of course, none of which should be particularly surprising, as nursing homes aren’t generally known as bastions of fun and freedom. So do things look better in the general, somewhat younger population?

The data collected from various CDC surveys measuring depression suggest that at any given moment, the rate of depression is somewhere between 6.8 percent and 8.7 percent. That means that in the U.S., somewhere between 1 in 11 and 1 in 14 people meet criteria for clinical depression — a lot of people.

What about the possibility of getting a mental disorder diagnosis within your lifetime?

Rates of reported lifetime diagnosis of depression were similar in 2006 (15.7%) and 2008 (16.1%).

The prevalence of lifetime diagnosis of anxiety disorders was slightly lower, with 11.3% in 2006 and 12.3% in 2008.

In 2007, NHIS [surveys found] 1.7% of participants had received a diagnosis of bipolar disorder, and 0.6% had received a diagnosis of schizophrenia.

As you can see, the lifetime risk of anxiety disorders rank closely with depression, yet they aren’t measured as carefully or closely by the CDC:

CDC surveys focus on depression, and they lack sufficient data on anxiety disorders. Anxiety disorders are as common in the population as depression and, like depression and severe psychological distress, can result in high levels of impairment. Moreover, the pathophysiologic characteristics of anxiety disorders are similar to those of depression and often are associated with the same chronic medical conditions.

The National Epidemiologic Survey on Alcohol and Related Conditions […] estimated that during 2001-2002, 14% of U.S. adults had an anxiety disorder: 7%, specific phobia; 3%, social phobia; 2%, generalized anxiety disorder; and 1%, panic disorder.

Remember, just somewhere between 7 to 9 percent of adults have clinical depression. This makes anxiety disorders almost twice as common as depressive disorder. Although rarely talked about as often as depression, anxiety can be just as debilitating and just as serious a problem. Yet today, the CDC doesn’t even measure it.

One last thing… The CDC is just figuring out what psychologists could’ve told them 20 or 30 years ago — that health problems are readily impacted by co-morbid mental health problems. The two are inextricably linked:

Increasingly, physicians and others who treat mental illness, as well as public health experts, are recognizing the substantial overlap between mental illness and diseases traditionally considered to be matters of public health concern. The ability of certain mental illnesses to exacerbate morbidity from several chronic diseases is well-established. Recent studies have explored the causal pathways from mental illness to certain chronic diseases, highlighting the need for more accurate and timely information on the epidemiology of mental illness in the United States.

This co-morbidity is a two-way street, too. Every time you see someone in a hospital bed being treated for one of those major health diseases you hear about in the news — such as heart disease or cancer — keep in mind that person also has mental health concerns. Most of the time, those mental health concerns — even it’s just anxiety related to the actual treatment or chances of recovery from the disease — are often overlooked altogether, or treated as minor, almost unrelated issues.

What this report did for the CDC was to summarize all of their current reporting tools that measure mental disorders, and figure out where there was overlap and where they were missing critical measurements. None of the CDC’s survey tools today specifically were designed to measure mental illness, however — a critical oversight. They are looking into correcting this problem, but it may be years before they start to systematically measure a wider range of mental disorders (rather than just a few) across the U.S.

Read the full CDC Report: Mental Illness Surveillance Among Adults in the United States