Gaps in Evidence (Haidt's After Babel)
Gaps in Evidence (Haidt's After Babel)
Haidt shows data on adolescent depression, but fails to present data for any other adolescent disorders, such as anxiety. Why is that?
In the Increases in Self-Reported Depression and Anxiety section of The Teen Mental Illness Epidemic Began Around 2012, Haidt presents evidence about adolescent depression and then jumps to trends among college kids. Adolescent anxiety is never mentioned.
Why did Haidt fail to present data about any other adolescent mental disorders besides depression?
Gaps in U.S. Prevalence Data
The unfortunate reality is that the tracking of adolescent mental disorders is limited.
Back in 2009, epidemiologist Kathleen Ries Merikangas noted the following in a section she titled The need for US national data:
The absence of empirical data on the magnitude, course, and treatment patterns of mental disorders in a nationally representative sample of US youth has impeded efforts essential for establishing mental health policy for this population.
Merikangas is highly qualified on this topic since she conducts large-scale surveys for the National Institute of Mental Health (NIMH) — including the first nationally representative study of adolescent mental disorders, the National Comorbidity Study-Adolescent Supplement (NCS-A).
Nearly a decade later, Merikangas published an editorial titled Time Trends in the Global Prevalence of Mental Disorders in Children and Adolescents: Gap in Data on U.S. Youth where she once again noted insufficient surveillance of adolescent mental disorders.
In particular, in the section titled U.S. PREVALENCE DATA, Merikangas writes:
Although there have been recent estimates of trends of specific conditions or behaviors in the United States, particularly depressive symptoms/syndrome and substance use and disorders, there is only one study that provided aggregate estimates of the prevalence of a comprehensive scope of common mental disorders and service patterns in a nationally representative sample of U.S. youth: namely, the National Comorbidity Adolescent Supplement, which was conducted more than a decade ago.
The U.S. does track various symptoms of mental disorders, but these are not measures according to criteria set by the Diagnostic and Statistical Manual (DSM) or by the International Classification of Diseases (ICD).
This problem does not affect only the data on minors. In Trends in anxiety among adults in the United States, 2008–2018: Rapid increases among young adults, the authors admit that their measure is based on a single NSDUH question about nervousness — far from DSM-5 criteria or ICD-10 criteria for Generalized Anxiety Disorder — and that this is the best they could do to estimate trends:
To our knowledge, this is the only measure that could be considered an indicator of anxiety that has been assessed consistently over the past decade in a nationally representative sample.
Current Surveillance among Children and Adolescents
According to Mental Health Surveillance Among Children — United States, 2013–2019, there are currently nine data systems with indicators of mental health among children and adolescents:
Autism and Developmental Disabilities Monitoring (ADDM)
National Health and Nutrition Examination Survey (NHANES)
National Health Interview Survey (NHIS)
National Survey of Children’s Health (NSCH)
National Survey on Drug Use and Health (NSDUH)
National Violent Death Reporting System (NVDRS)
National Vital Statistics System (NVSS)
School-Associated Violent Death Surveillance System (SAVD-SS)
National Youth Risk Behavior Survey (YRBS)
This may seem a lot at first, but the data on mental disorders offered by some of these systems is severely limited. The SAVD-SS, for example, merely collects data on the characteristics and circumstances surrounding school-associated violent deaths.
To understand measures directly related to the prevalence of adolescent disorders, it is best to look at Table 3:
We saw previously that Major Depressive Disorder (MDD) is measured in NSDUH by a series of questions corresponding to a DSM definition. It seems MDD, not counting substance abuse, is the only adolescent mental disorder measured annually, in a nationally representative sample, by DSM criteria — which leaves us with considerably less information on the prevalence and trends of other disorders.
Annual data on adolescent anxiety, for example, is limited to two questions answered by parents.
Types of Indicators
As we can see from the Table 3 section on depression, prevalence estimates can vary widely: from 5.8% to 36.7%!
Prevalence can be measured by symptoms such as sadness for MDD or nervousness for GAD — but an increase in the prevalence of a symptom within a population need not translate into a similar increase in the corresponding disorder, so we must be careful before equating a symptom trend with a disorder trend.
Prevalence can also be measured by asking about any current or past diagnosis of a disorder by a healthcare provider. A change in such a prevalence, however, could be due to changes in access to mental health care as well as due to changes in diagnostic practices.
Ultimately, there is no substitute for survey measurements based directly on DSM or ICD criteria when trying to determine disorder trends.
Indirect Indicators
It is still important, however, to look at indirect indicators when these are available. Are there substantial discrepancies between symptom and disorder trends? If so, it could be an important hint about mental health developments.
Similarly, if there are substantial discrepancies between trends based on reports by parents versus those based on reports by adolescents, that too could be an important clue.
It would be therefore helpful if Haidt reported and discussed the trends in all the relevant indicators made available by the nine surveillance systems listed above.
Conclusion
Although U.S. data on trends in adolescent disorders as defined by DSM or ICD criteria seem limited to depressive disorders and substance abuse, there are additional survey indicators that could help us better understand various developments in the mental health of adolescents.