What is psychopathy? - Chapter 27

Where does the term psychopathy come from?

Psychopathy is a term that dates from the early nineteenth century. Pinel introduced the term and used it for patients who behaved violently and inadequately. Since the 1940s, the term ‘psychopathy’ includes a certain combination of socially abnormal behavior and personality traits.

What are the clinical picture and diagnostic criteria of psychopathy?

In particular, much attention and research is paid to criminal psychopaths (such as serial killers and rapists), while there are also many non-criminal psychopaths. According to Lombroso (1867), a psychopath or criminal can be recognized by facial features such as wide jaws and deep-set eyes. In 1991 the PCL (‘Psychopathy Checklist’) was developed with which the degree of psychopathy can be reliably determined in prisoners and forensic patients. The PPI (‘Psychopathic Personality Inventory’) is used in the normal population. Psychopathy is a severe and difficult form of antisocial personality disorder (ASP), and is characterised by insensitivity, coldness, lack of empathy, pathological lying, and manipulation. Not everyone with an ASP develops into a psychopath. A precursor to psychopathy in childhood is conduct disorder.

How often does it occur?

The prevalence in the healthy population is estimated at 1-4%. 15-30% of the international patients are diagnosed with psychopathy (Hart, Hare & Forth, 1994). All these studies have only been performed on men. Women often score lower, partly due to the masculine description of the character traits. 

What are the aetiology and neuropathology of psychopathy?

The Low Fear Model

There is a specific number of neurocognitive limitations in psychopathy. Deviations have been found in the attention processes, forms of learning forms, emotion processing, and recognition of emotions (fear and sadness are less well recognized). The amygdala plays a central role.

The 'Low Fear Model' (LFM) is based on the abnormal (reduced) anxiety responses of psychopaths. Psychopaths do not have a normal anxiety response and coordinate their behavior less as a result of negative feedback (such as a prison sentence). They display the punished behaviours several times. Two criticisms of this model are:

1. Moral socialisation is taught not only by a conditioned fear response.

2. Psychopaths do not always display such a fear response to punishment.

The Response Modulation Hypothesis

The 'Response Modulation Hypothesis' (RMH) from Harpur and Hare (1990) assumes that peripheral stimuli (which do not receive immediate attention) are not properly processed. Response modulation is a rapid and relatively automatic shift in attention (away from the object of focus) that allows people to monitor peripheral information and actively use it if necessary. Psychopaths do not make this shift and consequently fail to adequately calculate the consequences of their behaviour and cannot use this information to adapt their behaviour. All clinical manifestations, including increased impulsiveness, are an expression of the failing integration of peripheral information. A shortcoming of this hypothesis is that empirical research has shown that psychopaths can indeed make this shift.

The Violence Inhibition Model

Following the criticism of the aforementioned attention model, Blair and colleagues (2005) developed the 'Violence Inhibition Model' (VIM). According to this model, everyone has a 'Basal Threat System' in the brain stem that is automatically activated by 'distress cues such as grief and anxiety. This system enables us to react to the pain of others and to learn that it is unacceptable to display behaviour that causes harm to others. As a result, we develop a 'violence inhibition' mechanism. Psychopaths have a disorder in this system. A shortcoming of this model concerns the notion that it cannot explain the emotional and attention disturbances that can be explained by the LFM and RMH.

What is the integrated emotion system?

The Integrated Emotion System (IES) model is an integration of the LFM and VIM (Blair and colleagues, 2005). The model consists of five systems:

1. The first system concerns in the transfer of sensory representations.

2. The second system plays a major role in making quick decisions based on the expected reward or punishment ('valence representation'). These valence representations are disturbed in people with psychopathy.

3. The third concerns motor responses and is also affected by input in the shape of valence representations.

4. The fourth system, the response selection system represents the expected reward or punishment associated with a stimulus, and possibly also with the response to that stimulus. The stimulus that yields the largest possible reward is selected as quickly as possible.

5. The fifth system is the 'response-gating' system that becomes active as soon as an expected reward pattern or punishment pattern is violated. This system changes the stimulus-response associations and increases or decreases the chance of displaying the same behaviour in the future.

The amygdala plays the largest role in this model. This model explains why aversive conditioning is not available for psychopaths. In conclusion, it can be said that two models assume a primary affective problem (the IES and the LFM) and one assumes a primary attention problem (RMH). Both affective models emphasize the importance of the amygdala. The difference between these two models is that the IES is more broadly applicable and the LFM mainly looks specifically at the insensitivity to punishment and sensation seeking.

What do neuroimaging techniques show?

The differences in neuroimaging data from all studies are difficult to compare due to the following reasons:

• The definition of the concept of psychopathy may differ markedly for each study.

• The collection, processing and analysis of data differs per study.

• There are only a few studies in which there is no comorbidity, drug use, or medication use and psychopathy is determined using the PCL-R.

• There is no consensus about the perfect control group yet.

• There is still no consensus about the correct cut-off score of the PCL-R.

The limited data available suggests structural deviations in the prefrontal-temporo-limbic structures (which are involved with affective information processing and learning processes). More specifically, a smaller prefrontal volume of the gray matter, the amygdala, the posterior hippocampal regions and the superior temporal gyrus. The corpus callosum has a slightly larger volume. The functional imaging studies suggest a lower metabolism and reduced fluid administration ('perfusion') in both temporal and frontal lobes. Recent studies into the electrophysiological processes involved in learning have shown that psychopaths have smaller ERNs ('error-related negativities'): this ERN occurs at the first signs of error detection. In addition, this (weak) signal is not used optimally.

What behavioral and cognitive impairments are there?

Remarkably, people often associate psychopathy with low SES and low intelligence, but objective research shows no correlation between these (Blair and colleagues, 2005). It seems that a higher intelligence is related to the earlier taking of criminal actions. In this case, the higher intelligence, in contrast to the normal population, is not an inhibitory factor for problem behaviour. The cognitive impairments are mainly limited to attention, learning, decision-making, and social cognition.

What role does attention play?

As the RMH model had already pointed out, deviations in the shift of attention to non-dominant stimuli are affected. Multiple studies have not been able to replicate this. The attention function would only fail in some situations, such as affective situations, due to a dysfunctional amygdala.

What are the disorders in learning and decision making?

Learning and decision-making based on punishment and reward have also been described earlier. Psychopaths would learn from rewards rather than punishment. The early error detection signal is very weak and is not being used optimally. Not only the detection, but also the awareness of errors is affected. In addition, the psychophysiological reactions after negative feedback are not so much present as in healthy controls. Finally, risk taking tasks have shown that psychopaths frequently make decisions that are riskier.

What disorders are there in social cognition?

The disturbances in social cognition are noticeable in emotion, empathy and affect. A wide range of emotion-processing operations are disturbed. Various studies show that the autonomous responses to emotionally negative stimuli are the same as the response to neutral stimuli. There would even be a preference for the negative stimuli. In the social context too, learning based on negative feedback is not successful. Psychopaths also have reduced apathy abilities: they respond less to other people's ‘distress’, they are inaccurate in assessing vocal affective information, and they are worse at recognizing emotions based on facial expressions. In contrast to non-psychopathic criminals, psychopathic criminals have more difficulty in distinguishing between "moral transgression" (behavior that leads to harm to a person) and "conventional transgression" (behavior that disrupts social order such as speeding).

How does aggression relate to endocrine and genetic factors?

Psychopathy is often associated with aggression, and aggression is associated with serotonin, dopamine and noradrenaline. A lower level of serotonin induces uninhibited aggressive behavior. SSRIs and tryptophan can increase serotonin levels and reduce aggression. However, serotonin is part of a complex network and such simple drug treatment is therefore not necessarily effective (Kraemer, Schmidt & Ebert, 1997). There is a less strong relationship between dopamine and aggressive behavior. Sometimes antipsychotics are prescribed to block the dopamine receptors. Noradrenaline prepares the body for aggressive behavior (the fight part of the 'fight-or-flight' response). Here too, aggressive behaviour diminishes by administering drugs that block noradrenaline β receptors. In the area of ​​endocrine factors, there is a strong positive correlation between testosterone and violent and antisocial behavior. The increased level of testosterone can be a cause or a consequence of a dominant status. Psychopaths cannot transform social dominance into a socially acceptable manifestation. In combination with reinforcing factors (such as cognitive deficits and social incompetence), social destructive behavior develops.