Are Epidemiology Studies of Risky Environments Mostly Worthless?

Various risk factors for psych disorders are hardly experienced uniformly.

Posted Dec 20, 2019

Flickr Epidemiology by Twitter-trends de 2.O CC by 2.0
Source: Flickr Epidemiology by Twitter-trends de 2.O CC by 2.0

In my post from December 24, 2012, "Why Psychotherapy Outcome Studies are Nearly Impossible," I discussed the large number of variables that are not taken into consideration in research studies of outcomes of various psychotherapy treatments in various diagnostic groups. This issue brings any conclusions drawn from them into serious question. These variables include variations in therapist techniques that aren’t measured, sampling problems with people that can have wide variations in their proclivities and sensitivities, problems with finding an active control treatment, the lack of double-blinding, and, most importantly, lack of complete candor by subjects.

Many of the same issues apply to epidemiological research into environmental risk factors for various psychiatric disorders. Most studies try to measure the effect of a single environmental factor on a single outcome—something that rarely exists in the real world—such as the likelihood that people who vape will develop depression.

In a “viewpoint” article from JAMA Psychiatry published online on June 6, 2018, by Guloksuz, van Os, and Rutten ("The Exposome Paradigm and the Complexities of Environmental Research in Psychiatry"), the authors discuss characteristics of the environment as they actually do function in the real world. They speak of multiple “networks of many interacting elements…” [emphasis mine].

Individuals are exposed to all of these elements as they come and go—or accumulate over time—so that one single exposure to one element usually means very little. Exposure is also “dynamic, interactive, and intertwined" with various other elements including the internal propensities of individuals, what individuals do differently within different contexts, and the external environment itself—which is constantly changing.

Last but not least, each individual attributes a different, and sometimes changing, psychological meaning to everything that happens to them. This meaning attribution can alter the effects of each environmental exposure dramatically. People can, despite appearances sometimes to the contrary, think and reason about things.

One recent example are studies that attempt to answer the question: Is having an abortion traumatic for the woman? These studies are usually designed more for the purpose of making political points in the abortion debate rather than to answer the question scientifically. Be that as it may, at the very least, her beliefs and attitudes about abortion make a huge difference in whether or not a given woman will find the experience disturbing. Religious upbringing, beliefs about when life begins, and a whole host of other factors are never controlled for in these studies. Therefore, it can be argued that such studies are completely useless.

Each environmental factor confers risk for a "diverse set of mental disorders." The factors interact with each other so they are not independent. They are time-sensitive. They are dose-dependent even within similar environments, meaning individuals are not exposed to them at the same level. Added to that are gene-environment interactions. The various exposures can be subject to being confounded by each individual’s differing genetic propensities.

With all that to consider, drawing final conclusions from a few studies, rather than just discussing possibilities, does not cut it as real science. Nonetheless, some in the field tend to believe in those conclusions as if they were gospel.