An MRI scan cannot diagnose psychopathy or identify sociopaths

This past week I was talking on the telephone with my student and research assistant when he was mugged by a group of 5-7 thugs. One hit him from behind, knocking him down and another punched him in the abdomen. Ironically, among the items stolen was a copy of “Without Conscience” by Robert Hare.

Yesterday, my student asked me, “Those guys in the group who do have empathy and guilt, how do they feel about doing this? What makes them do it?” To which I replied, “I don’t think they feel a thing. They are likely all psychopathic (sociopaths). No one wants to admit just how many of them there are. So they draw an artificial line based on the PCL-R (a psychopathy test) and say these thugs are psychopaths and these thugs are non-psychopaths. They call them non-psychopaths even though their scores on the test are far from normal. They do this because they want to hold on to hope that most of them can change.”

Dr. Reid Melloy, a forensic psychologist with years of experience working with criminals has a method of classifying them that I think is more correct. He has four groups, not two, based on the PCL-R, non-psychopaths, and mild, moderate and severe psychopathy. I do concede that the thugs that assaulted my student likely had the syndrome to varying degrees; and we know the ring leader is likely severely affected.

That gets me to a recent article that received a great deal of news coverage. In one Fox News article were comments from experts who in the past I have criticized for irresponsible public comments. The article discusses data from a study published in a top journal, it doesn’t give the title but it is, The Antisocial Brain: Psychopathy Matters a Structural MRI Investigation of Antisocial Male Violent Offenders.

The title should say, “the degree of psychopathy matters”. When you see stories like this you have to watch out because my colleagues have rotating definitions of psychopathy that they pull out depending on what they need to fit their data. In some studies like this one, they use a cut-off high PCL-R score. In other studies they separate offenders into groups depending on whether or not they show empathy and remorse. So groups may contain the same PCL-R score but be defined in terms of differing symptoms.

The study basically showed that higher scores on the PCL-R are associated with a higher likelihood of finding a shrunken “emotional brain”. Before you go writing me asking that your ex be forced to undergo an MRI which will prove the presence of psychopathy, let me tell you what is not in the news article. You cannot use an MRI scan to diagnose psychopathy.

A diagnostic test has to be sensitive, meaning that it picks up your ex and everyone else with the condition. Well we already know that there is mild, moderate and severe. So do we want the test to pick up the mild or the severe group? That will depend on what your ex actually scored on the PCL-R. I am sure that a “mild” case of psychopathy, does not make for a good life partner. That is why for the purposes of Love Fraud any comparison between “ASPD” and psychopathy is meaningless.

A diagnostic test also has to be specific meaning that only psychopaths show the abnormality. There is no test for psychopathy that is sensitive and specific enough to be useful. This article only shows us the obvious, that very high levels of psychopathy are more likely to be related to observable changes in the brain than are lower levels of psychopathy.

Since the brain produces behavior, their brains have to be different. The behavior they produce is different. All of the thugs who attacked my student to steal “without conscience” have something wrong with their brains.