A Little Clarification on Psychopathy

HARE, R. (2006). Psychopathy: A Clinical and Forensic Overview Psychiatric Clinics of North America, 29 (3), 709-724 DOI: 10.1016/j.psc.2006.04.007

Guay, J., Ruscio, J., Knight, R., & Hare, R. (2007). A taxometric analysis of the latent structure of psychopathy: Evidence for dimensionality. Journal of Abnormal Psychology, 116 (4), 701-716 DOI: 10.1037/0021-843X.116.4.701

So there's some confusion about the differences between the diagnoses of psychopathy and Antisocial Personality Disorder (APD). Well, to make matters worse, the Diagnostic and Statistical Manual of Mental Disorders (DSM) goes and equates the two. Dr. Geiselman has said in his lectures that the difference, in his experience, is that psychopathy is characterized by delusions, hallucinations, and other sensory phenomena. Okay, for the test you're going to want to go with this definition; however, I tend to prefer the definition offered by one of the primary researchers on psychopathy, Robert Hare. Did I ever mention how much great forensic research comes out of Canada? Hare's based in the University of British Columbia, and he developed the Psychopathy Checklist thirty years ago, which has become the instrument to assess psychopathy.

As summed up in a recent overview (Hare 2006), psychopathy can be subdivided into four main factors:

1. interpersonal (glibness, narcissism, conning behaviors, etc.)
2. affective (lack of remorse, shallow affect, etc.)
3. lifestyle (need for stimulation, parasitism, impulsivity, etc.)
4. antisocial (criminal versatility, poor control, etc.)

Notice there's no mention of hallucinations or disordered thinking among these factors. So how does this compare with APD? According to the DSM, they're synonymous. However, taking a real look at them, APD is diagnosed entirely by manifest behaviors, while psychopathy is an attempt to define a personality type by the underlying cognitive and relational patterns. As Lykken (quoted in Hare 2006) puts it: "Identifying someone as ‘having’ APD is about as nonspecific and scientifically unhelpful as diagnosing a sick patient as having a fever or an infectious or a neurological disorder." APD is the symptom; psychopathy is the disease. There's significant overlap in diagnoses of APD and psychopathy, but there are also significant numbers of people who fail to meet both definitions.

There have been numerous attempts to put psychopaths into a taxon, a group used for classification - either you're psychopathic or you're not. However, these attempts have consistently failed to find evidence supportive of a taxonomic system. Hare (2007), in a large and diverse sample, again tried to perform a taxometric analysis, but could only find evidence for dimensionality. What does this mean? Well, there are several reasons why a legitimate taxon could be covered up in an analysis, but if psychopathy is truly dimensional, it means that there are no clear, defining lines between those with psychopathy and those without. It may just be a scale on which a given person is either high, moderate, or low.