False Assumptions in Personality Disorder Research, Part II

Researchers often ignore how people actually behave in drawing conclusions.

Posted Jun 29, 2018

This is the second in a series of posts that discusses false and unacknowledged assumptions that are rampant in the personality disorders research literature and which lead to false or misleading conclusions. I presented this information during a panel discussion on personality research at the 2018 annual meeting of the American Psychiatric Association in New York City.

Wikimedia Commons,  Detection of Suspicious Persons, public domain
Source: Wikimedia Commons, Detection of Suspicious Persons, public domain

False Assumption #2: Social Judgment is exercised independently from prior experience – ignorance of error management theory.

An article by Nicol, Pope and others called “Social judgment in borderline personality disorder” (PLoS ONE [Electronic Resource].  8(11): e73440, 2013) reported an investigation of the ability of participants with borderline personality disorder (BPD) to make assess the mood or intention of other individuals from pictures of the faces of strangers. They found that there was a correlation between scores on a Childhood Trauma Questionnaire (CTQ) and seeming bias towards judging faces as unapproachable. 

Other studies have shown that patients with BPD are actually better at reading faces than controls, so in trying to draw any conclusions of course we have to figure out why different studies get different results. But ignoring that for the time being, let us just look at this one study abstract in isolation.

The conclusions were that the subjects with BPD had “significant impairments” and "difficulties" in making judgment. To be fair, the authors also used the words "heightened sensitivity to perceiving potential threat," which is actually a far more accurate description of their findings. But it is the words "impairments'" and "difficulties" that will be the ones that jump out at most readers. And in the body of the paper, those terms are in fact more in line with the conclusions discussed by the authors than the phrase "heightened sensitivity."

A false a priori assumption here involves ignorance of the implications of something called error management theory. A clue about this is where the article mentions that the patients with BPD were far more traumatized as children than the controls. That being the case, it is highly likely that the people in the social environment of the BPD subjects were far more likely to have hostile intentions than those of the controls. In such an environment, you’d have to be stupid not to generally have a high index of suspicion when evaluating the faces of people. To make fewer errors that could lead to a disastrous result for yourself, one in such a situation learns to err on the side of caution in evaluating possibly ambiguous facial expressions.

The assumption the authors seem to be making is that somehow the BPD subjects were just naturally worse at reading faces, rather than they were justifiably more suspicious of other people!

So the assumptions they seem to making that need to be questioned are:

1. We can just ignore the social context of research subjects in making these sorts of judgments about people’s abilities.

2. It is true that people rarely if ever use their brains to develop strategies for dealing with other people that have little to do with their innate abilities.

False Assumption #3: Confusion of Correlation and Causation: attributing a correlation to a specific causal relationship when other models explain the results better.

The mental health professions these days seems to want to blame their patients' repetitive problematic or self-destructive behavior on just about anything except what I believe to be, in the significant majority of cases, the primary causes: family dysfunction and adverse childhood experiences (ACE’s). For example, an observed increase in aggressive thoughts following the playing of violent video games by adolescents sometimes leads some researchers to have concluded that the games are a major risk factor for the development of youth violence. The fact that most compulsive video game players are inveterate couch potatoes who do not get out much never entered into discussions.

Not surprisingly, a recent longitudinal study (Ferguson et. al., J. Psychiatr Res 2012; 46: 141-146), showed that, by taking other variables into account such as intra-family violence, the correlation between video games and even short-term aggression could no longer be established.

Another older paper from the same lead author (Ferguson and Rueda,  J Exp Criminol, 2009; 5:121-137) showed that aggressiveness in the laboratory, as expected, did not correlate with violent acts in real life. Focusing on minor targets like video games risks leading social activists and public policy makers to ignore the far more important causes of youth violence like child abuse.

When it comes to searching for causes for drug abuse, this same false assumption comes up all the time. In studying marijuana use, for example, the fact that people who feel the need to be stoned all the time clearly have other problems is often ignored; the idea that their problems came only after the marijuana use is often assumed instead.

For example, A study out of Australia and New Zealand: “Young adult sequelae of adolescent cannabis use: an integrative analysis” by Edmund Silins and others. (Lancet Psychiatry, 2014; 1: 286–93). Notice that even the title presumes that problematic behavior occurs only after the marijuana use. The authors concluded, based on just a few variables, that there were clear, consistent dose-related associations between the frequency of adolescent cannabis use and adverse young adult outcomes, such as less likelihood of high school completion and substantially increased odds of later cannabis dependence and use of other illicit drugs.

The authors claimed to control for confounding variables, but most of these "controlled" variables were unrelated to ACE’s or ongoing family chaos. They were such things as age, sex, ethnicity, socioeconomic status and mental illness. The authors did control for a few possibly relevant parental variables like alcohol use, tobacco use, divorces, and history of depression. But not for how the parents actually behaved around their children, how they treated their children, child abuse or neglect, how chaotic the home environment was, or how and how consistently the children were or were not disciplined.

Again, frequent drug use is very likely to be a sign that the teens already had emotional problems before they even started smoking - and that it was these problems that predate the drug use that were the real cause of both the drug use and the poor performance.