Among psychiatry’s critics, the notion that there is an “epidemic” of mental illness in the U.S. is one of the most widely-held beliefs. More radical versions of this narrative implicate psychiatrists and psychiatric medication for the alleged proliferation of mental illness –essentially claiming that psychiatrists are worsening the very illnesses they purport to treat. But what is the evidence for such an “epidemic” of mental illness, in the first place?
In medical science, an “epidemic” usually refers to an infectious disease that has spread rapidly to many people—witness, for example, the recent Ebola epidemic. More broadly, an epidemic denotes any illness that appears with a frequency clearly in excess of what is normally expected.
Incidence vs. Prevalence
When we speak of an illness’s frequency, we are usually referring to its incidence and prevalence. Basically, incidence refers to the number of new cases of the illness within a specific period of time.
Prevalence refers to the total number of persons sick with the illness during a particular period—both old and new cases– regardless of when the illness began. So–over the past few decades, has the incidence or prevalence of psychiatric illness reached “epidemic” proportions in the U.S.? At least with respect to the most serious psychiatric illnesses in adults, the answer is no. And recent data suggest this may also be the case in children and adolescents, though our data base is far from ideal.
While many types of psychiatric illness may be “serious,” the term “serious mental illness” (SMI) is defined by the National Institute of Mental Health as a psychiatric disorder “…resulting in serious functional impairment, which substantially interferes with or limits one or more major life activities.”
Although major depressive disorder, bipolar disorder, and schizophrenia are commonly discussed as prime examples of SMI, the NIMH definition could apply to post-traumatic stress disorder (PTSD), anorexia nervosa or any other psychiatric disorder that fits the impairment criteria.
One method of comparing the occurrence of SMI now to years past is via the National Survey on Drug Use and Health (NSDUH)–an annual nationwide survey involving interviews with approximately 70,000 randomly selected individuals aged 12 and older. NSDUH data over the past decade shows, overall, very little change in rates of SMI in this country.
Data Shows Decline
For example, in 2013, there were an estimated 10.0 million adults aged 18 or older in the United States with SMI in the past year—representing 4.2 percent of the adult population. This number compares with 5.0% in 2010 and 4.8% in 2009. And if we go back to the NSDUH data from 2002, we find that 8.3% of adults in the U.S. were found to have serious mental illness during the 12 months prior to being interviewed.
So, if anything, it seems that SMI prevalence in this country has actually declined over the past decade or so. Going back farther, there is no reason to revise this conclusion. For example, using other national survey data, a group of technical experts estimated SMI in 1990 at about 5.4% of the adult population. Taken together, these data do not point to an “epidemic” of serious mental illness in recent decades.
NSDUH studies don’t yield incidence or prevalence rates for specific disorders such as schizophrenia, bipolar disorder or major depression. However, other sources of information suggest that the incidence and prevalence of these conditions, word-wide, have remained fairly steady over the past 50 years.
For example, while rates of schizophrenia differ considerably from country to country, a 1997 review found that overall incidence rates appear relatively stable across countries and cultures, over at least a 50-year period. This conclusion doesn’t point to an “epidemic” of schizophrenia, following the introduction of antipsychotic medication in the late 1950s and 60s.
Indeed, if antipsychotic medications actually worsened schizophrenia, we would expect to see substantially rising prevalence rates of schizophrenia over the past five decades—but there is no credible evidence of this happening in the U.S. or worldwide.
This doesn’t mean that everyone with schizophrenia ought to take antipsychotic medications indefinitely. A certain percentage of carefully-selected patients with schizophrenia may be able to do without these drugs, once they are clinically stable. But there is no convincing evidence that antipsychotic medications are driving an “epidemic” of schizophrenia (see the review by Dr. Joseph Pierre).
With regard to major depressive disorder, data from the Baltimore Epidemiologic Catchment Area study—a survey involving more than 175,000 household residents– revealed no evidence of an “epidemic of depression” in the period from 1981-2004.
This timeframe is the same period that witnessed a marked increase in the use of antidepressant medication in the U.S. If antidepressant treatment was truly “driving” an epidemic of major depression, we would expect to see a sharply rising incidence and/or prevalence of this condition—but neither has been detected for the U.S. population as a whole.
Further confirmation of the “non-epidemic” of major depression is provided by eight-year NSDUH data. These show that the percentage of adults who had a major depressive episode in the past year remained stable between 2005 (6.6 percent) and 2013 (6.7 percent).
What are Reliable Measures?
Some who argue that actual psychiatric illness is on the rise in the U.S. point to increasing rates of psychiatric disability determinations—for example, increased numbers of those “disabled” by mental disorders who qualify for Supplemental Security Income (SSI) or Social Security Disability Insurance (SSDI).
But SSI/SSDI determinations are in no sense a reliable measure of the actual incidence (new cases) or prevalence (total cases at a given time) of psychiatric disorders—nor are they necessarily an indicator of treatment success or failure.
Disability determinations by the Social Security Administration (SSA) are largely administrative hearings—not medical-psychiatric evaluations—and may depend, for example, on how well-prepared the applicant is when presenting his or her “case” to the evaluator—who may or may not have medical or psychiatric expertise.
Similarly, rising rates of medication prescription—though of potential concern from the clinical and societal standpoint—cannot serve as a reliable proxy for actual incidence or prevalence rates. Prescribing patterns may be subject to fluctuations owing, for example, to rates of direct-to-consumer advertising or to public and professional awareness of a particular condition.
Neither can office-based rates of psychiatric diagnoses serve as reliable indices of illness incidence or prevalence, since clinicians differ widely in their application of DSM diagnostic criteria, which are often ignored.
So, for example, rising rates of office-based diagnosis of bipolar disorder in children and adolescents—admittedly, a matter of societal and medical concern—do not necessarily indicate an increase in actual cases of bipolar disorder in the general population.
Similarly, rates of treatment for a given disorder may be misleading with respect to actual prevalence of the illness, since psychiatric treatment is widely subject to socioeconomic variables like insurance coverage and access to mental health practitioners.
In sum: though important for several reasons, none of these measures—disability rates, prescribing patterns or rates of office-based diagnosis—is a valid means of determining an illness’s incidence or prevalence. None is a substitute for applying consistent diagnostic criteria and/or using structured clinical interviews in comparable populations over long periods of time.
Ideally, clinical assessments should be made at the time of the person’s illness, rather than inferred retrospectively via survey responses—but on a large scale, this undertaking would be daunting. Unfortunately in the U.S., we have very few carefully collected, prospective data with which to track prevalence and incidence of psychiatric disorders, from childhood through adulthood.
Psychiatric Illness in Younger Populations
Thus far, we have reviewed data primarily derived from adult populations. But what about children and adolescents? Is there really an “epidemic” of mental illness in such younger populations, as some have claimed?
** Recently, Dr. Mark Olfson and colleagues looked at rates of severe mental impairment among young people who receive mental health care in the United States. Based on survey data involving more than 50,000 subjects six to 17 years of age, the authors found that the percentage of young people with relatively severe mental health impairment actually declined from 12.8% in 1996–1998; to 11.9% in 2003–2005; to 10.7% in 2010–2012.
It’s interesting to note that this decline in serious mental impairment coincided with increasing prescription of antidepressants in this younger population. Though no firm conclusions can be drawn from this temporal association, there is no “signal” from the Olfson et al data suggesting that antidepressants are driving up rates of serious mental impairment in younger populations.
Of course, individual responses to these medications can vary considerabl, and all patients need to be carefully monitored for adverse reactions or side effects—particularly younger patients.
Other data in younger psychiatric populations also undermine the “epidemic” narrative. For example, Dr. E. Jane Costello and colleagues reviewed epidemiologic studies of children born between 1965 and 1996. All the studies reviewed used structured diagnostic interviews to make formal diagnoses of depression.
Twenty-six studies were identified, generating nearly 60,000 observations on children who had received at least one structured psychiatric interview. The authors concluded that there is no evidence for an increased prevalence of child or adolescent depression over the past 30 years, and that
“…public perception of an ‘epidemic’ may arise from heightened awareness of a disorder that was long under-diagnosed by clinicians.”
Similarly, Dr. Kathleen R. Merikangas and colleagues reported on results from the National Comorbidity Study-Adolescent Supplement (NCS-A), which examined lifetime prevalence data of mental disorders in a nationally representative sample of U.S. adolescents.
This study, too, found no evidence of substantially increased rates of major depression, compared with earlier NCS data.
^^Finally, with respect to bipolar disorder in younger populations, a recent review by Goldstein and Birmaher found no evidence of increasing prevalence of bipolar spectrum disorders over time, as ascertained by rigorous semi-structured interviews.
There is very little credible evidence to support the claim that serious psychiatric disorders are on the rise, much less that there is a “raging epidemic” of mental illness in the U.S.—either in adult or younger populations.
On the contrary, rates of serious mental illness appear to be either declining or stable in this country. Relatively stable rates also apply with respect to the incidence and prevalence of, for example, major depression and schizophrenia.
The actual occurrence rates of mental illness cannot be reliably inferred from changes in medication prescription rates; office-based diagnosis or treatment rates; or rates of putative “disability” attributed to mental illness. Only the uniform application of specific clinical criteria over long periods of time, and/or the use of structured clinical interviews, can yield reliable information on incidence and prevalence.
There is no credible epidemiological evidence that psychotropic medication per se has led to rising rates of serious mental illness or increased rates of any specific psychiatric disorders in the general population.
And, of course, absent a demonstrable “epidemic” of mental illness in the U.S., the speculative claim that there is a “biological cause” for the epidemic is nonsensical on its face.
Notwithstanding these conclusions, we need to investigate why office-based diagnosis and treatment is increasing for some psychiatric disorders.**
We also need better prospective methods of tracking incidence and prevalence of psychiatric illness in this country.
Equally urgent, we need to ensure that those with serious psychiatric illness—who often do not receive any professional care at all– have access to care and treatment by mental health professionals.
This article was modified and condensed from a piece published in Psychiatric Times.
^^ Rates of bipolar disorder vary considerably from country to country and some evidence points to higher lifetime prevalence rates in the U.S. than in several other countries. This “…may reflect methodologic differences in diagnostic procedures or assessment methods as well as true differences in disease prevalence.” (Merikangas et al, Arch Gen Psychiatry. 2011;68(3):241-251).
** I have not dealt with Attention-Deficit Hyperactivity Disorder (ADHD) in children because the criteria for this condition have changed significantly over the past 40 years, and estimates of prevalence depend crucially on how DSM criteria are applied by clinicians.
The Center for Disease Control reports that surveys asking parents whether their child received an ADHD diagnosis from a health care provider show that the percentage of children with an ADHD diagnosis increased from 7.8% in 2003 to 9.5% in 2007 and to 11.0% in 2011.
But even assuming that the diagnoses provided by clinicians were valid, a roughly 3% increase over eight years would not qualify as an “epidemic.” Commenting on these trends, the CDC notes: “It is not possible to tell whether this increase represents a change in the number of children who have ADHD, or a change in the number of children who were diagnosed. Perhaps relatedly, the number of FDA-approved ADHD medications increased noticeably since the 1990s, after the introduction of long-acting formulations.” [http://www.cdc.gov/ncbddd/adhd/timeline.html]
Readings and References
Angell M: The Epidemic of Mental Illness: Why? The New York Review of Books. June 23, 2011.
Costello EJ, Erkanli A, Angold A: Is there an epidemic of child or adolescent depression? Journal of Child Psychology and Psychiatry 47:12 (2006), pp 1263
DeAngelis T: Children’s mental health problems seen as ‘epidemic.’ American Psychological Association.
Eaton WW, Kalaydjiann A, Scharfstein DO et al: Prevalence and incidence of depressive disorder: the Baltimore ECA follow-up, 1981–2004. Acta Psychiatr Scand. 2007 September; 116(3): 182–188
Epstein J, Barker P, Vorburger M, Murtha C: Serious Mental Illness and Its Co-Occurrence with Substance Use Disorders, 2002. http://www.ce-credit.com/articles/100995/CoD.pdf
Goldstein BI, Birmaher B. Prevalence, clinical presentation and differential diagnosis of pediatric bipolar disorder. Isr J Psychiatry Relat Sci. 2012;49(1):3-14.
Hafner H, an der Heiden W. Epidemiology of Schizophrenia. Can J Psychiatry 1997;42:139–151
Kessler, R. C., Berglund, P. A., Zhao, S., et al: The 12-month prevalence and correlates of serious mental illness (SMI). In R.W. Manderscheid & M. A. Sonnenschein (Eds.), Mental health, United States, 1996 (pp. 59-70, DHHS Publication No. SMA 96- 3098). Rockville, MD: Substance Abuse and Mental Health Services Administration, Center for Mental Health Services.
Merikangas KR, He J-P, Burstein M et al: Lifetime Prevalence of Mental Disorders in US Adolescents: Results from the National Comorbidity Study-Adolescent Supplement (NCS-A). J Am Acad Child Adolesc Psychiatry. 2010 Oct; 49(10): 980–989
Whitaker R. Psychiatric drugs and the astonishing rise of mental illness in America. Ethical Human Psychiatric Times. Ethical Human Psychology and Psychiatry, Volume 7, Number I ,Spring 2005
Moreno C, Laje G, Blanco C, et al. National trends in the outpatient diagnosis and treatment of bipolar disorder in youth. Arch Gen Psychiatry. 2007;64:1032-1039.
National Institute of Mental Health. Rates of bipolar diagnosis in youth rapidly climbing, treatment patterns similar to adults. http://www.nih.gov/news/pr/sep2007/nimh-03.htm
González HM, Vega WA, Williams DR, et al. Depression care in the United States: too little for too few. Arch Gen Psychiatry. 2010;67:37-46.
Olfson M, Druss BG, Marcus SC, Trends in Mental Health Care among Children and Adolescents N Engl J Med 2015; 372:2029-2038
Pierre J: Do Antipsychotics Worsen Schizophrenia in the Long-Run? https://www.psychologytoday.com/blog/psych-unseen/201408/do-antipsychotics-worsen-schizophrenia-in-the-long-run
Pies R: Does psychiatry medicalize normality? Philosophy Now. Volume 99, November/December 2013. Accessed at:
Pies R: Is There Really an “Epidemic” of Psychiatric Illness in the US? Psychiatric Times. May 1, 2012. Accessed at: http://www.psychiatrictimes.com/articles/there-really-%E2%80%9Cepidemic%E2%80%9D-psychiatric-illness-us
Results from the 2010 National Survey on Drug Use and Health: Mental Health Findings. http://www.samhsa.gov/data/sites/default/files/NSDUHmhfr2010/NSDUHmhfr2010.htm#1.4
Results from the 2013 National Survey on Drug Use and Health:
Mental Health Findings. http://www.samhsa.gov/data/sites/default/files/NSDUHmhfr2013/NSDUHmhfr2013.htm#2-3
Serious mental illness among U.S. adults. National Institute of Mental Health. Accessed at:http://www.nimh.nih.gov/health/statistics/prevalence/serious-mental-illness-smi-among-us-adults.shtml
Substance Use and Mental Health Estimates from the 2013 National Survey on Drug Use and Health: Overview of Findings. http://www.samhsa.gov/data/sites/default/files/NSDUH-SR200-RecoveryMonth-2014/NSDUH-SR200-RecoveryMonth-2014.htm
Ultimate Social Security Disability Guide: SSDI, SSI, How to Win, Information
Social Security Disability Hearing and How to Prepare for Disability Hearing.
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