Socioeconomic status has long been considered as a potential explanation for discrepancies in professional expectations, lifestyle trends, and mental and physical health in America. The relationship between household income and mental disorders has been especially thoroughly examined. Numerous longitudinal studies over the years have consistently found a damningly strong correlation between the two variables. In fact, a 2011 study (1) examining almost 35,000 American adults found that the presence of most lifetime Axis I and Axis II mental disorders, including anxiety and personality disorders, were associated with lower income levels.
This correlation between poverty and mental health has apparently produced a linear causal relationship pointing from the former to the latter. From this association, numerous mental health initiatives have arisen to fight for a better system and for interventions to benefit lower income Americans. While successful, these initiatives take largely reactive measures to mental illness: providing resources once symptoms appear, treatment options for those afflicted, educating families on warning signs, etc. After all, it’s hard to proactively treat an issue stemming from the larger societal causes of income inequality, poverty, and decreasing class mobility. But what if there is an additional factor, another point between socioeconomic status and mental health?
In a letter (2) to the Emerging Infectious Diseases Journal in 1998, Edward McSweegan voiced his concern that there may be a connection between infectious diseases and mental illness. Streptococcal infections in children increasing risk for OCD and Tourette syndrome, Lyme disease causing memory deficits, and depression in the aftermath of leptospirosis are all specific concerns which McSweegan draws upon as he illustrates the need to consider neuropsychiatric disorders as potential manifestations of infectious diseases in 1998.
Now, 20 years later, we have scientific evidence of such relationships and even distinct biological mechanisms accounting for some of them. A Brazilian study (3) published in 2005 showed an almost three-fold increase in psychotic symptoms of adults who had childhood meningitis compared to those who didn’t. These findings were also reinforced by a 1997-published study (4) of a cohort from Northern Finland, and more recently, by a 2012 meta-analysis (5) of published literature by Dr. Golam Khandaker from the University of Cambridge. The 2012 study involved 1035 cases and over 1.2 million controls to reveal that childhood central nervous system viral infections significantly increased (even doubled!) the risk of adult-onset schizophrenia. Khandaker’s work and numerous additional studies since have named a swathe of viral infections responsible for increased psychiatric risks for a wide variety of mental health diseases, including generalized anxiety disorder and major depression. Rubella, hepatitis C, influenza A (H1N1), and more are amongst the noted viruses (6,7).
Healthcare has a price tag, so obviously treatment options, if available, are more difficult to procure for those in lower socioeconomic levels. Even something as trivial as getting a vaccine becomes a headache if you don’t know how many meals you’ll have to pass on to afford it or if you can’t find time to set a doctor’s appointment between the 3 jobs you’re working. Interestingly enough, a 2017 study (8) found a “Vaccination Kuznets Curve”, that the probability for children’s vaccination currency decreases on both sides of the income spectrum. Nonetheless, this tendency on both ends of the distribution can be assumed to be caused by two different causes: parental choice on the wealthier side and financial or socioeconomic inability on the poorer side (8).
It’s no surprise then that those in lower socioeconomic levels, who have the most difficulty resisting and treating viral infections even when they’re preventable by vaccination, are at greater risk for severe disease outcomes (10). Sometimes, this risk proves fatal, but even surviving the disease doesn’t relinquish the patient from potential future effects on themselves or sometimes even their children. The infectious diseases which lower socioeconomic groups face at greater risk may sound familiar to you. Hepatitis C, influenza A, and leptospirosis, just to mention a few – all infectious diseases which have been tied to some degree to psychiatric disorders, adult-onset or symptomatic.
Mental health is obviously not a simple subject which can be explained by a few factors, and frustratingly enough can’t be easily categorized attributed to any single social aspect. Otherwise, there would already be a solid solution in some section of a public health textbook. But there isn’t, and as more research is conducted in mental health with respect to economics, epidemiology, and even ecology, the connection between physiological and psychological well-being becomes increasingly visible. The unique pathologies of the various mental illnesses are gradually being discovered and while there are definite ties to socioeconomic circumstance, perhaps it’s time to widen the focus of the fight against mental illness beyond its current scope.
Poverty is a complex issue which can’t be treated with medicine, but a pathogen is an entirely different matter. With an infectious disease basis, we can tackle mental health in lower socioeconomic groups from a new perspective by treating it not as a byproduct, not an unavoidable environmental phenomenon, but as a diagnosable symptom. A condition which rather than being caused by an overarching, towering giant of a social issue, has a biological basis and can therefore be treated more immediately at an individual level.
A virus can be vaccinated against, a bacterial infection treated, and maybe, with a new approach, a mental disorder prevented.
Edited by: Julia Bulova
Illustrated by: Caroline Cao