I'll admit this seems like an odd question with an obvious answer. Most people would say that a criminal is anyone convicted of a crime. However, there is a difference between someone who has merely been convicted of a single crime and someone with a pattern of criminal behavior. Repetitive criminals may be psychopaths or sociopaths. Fictional characters like Hannibal Lechter or Tony Soprano are good examples of sociopathic or psychopathic personalities.
It might be a bit disconcerting to know that people like this actually exist and that they've been around for a long time. In 1837 an English psychiatrist named James Pritchard wrote a book entitled Treatise on Insanity in which he described people who lacked the ability to form attachments to others and who were unable to experience normal human affection or emotions. These individuals had little regard for the feelings or rights of others, however they didn't have the hallucinations or impaired cognitive functioning that was seen in other psychiatric disorders. Dr. Pritchard coined the term 'moral insanity' to describe this disorder, which he felt was a defect in area of the brain responsible for moral reasoning. Around this time the American Journal of Insanity (which later became the American Journal of Psychiatry) published several individual case studies of homicide offenders, all of which were entitled "A Case of Homicidal Insanity". They were all essentially just case descriptions of murderers. The letters to the editor of the journal following these case studies debated the validity of 'moral insanity' as a mental illness. The difficulty was that the term 'insanity' implied that from a legal standpoint the criminal should not be held responsible or punished for his behavior. Eventually the term 'moral insanity' was dropped in favor of the term 'psychopath', a term proposed by a Nineteenth Century German psychiatrist.
More recently, the term 'sociopath' has been used instead of 'psychopath'. This latest change happened because people were getting confused by the 'psycho' part of the psychopathy label---psychopathy doesn't mean that the criminal is psychotic. Actually, neither sociopathy nor psychopathy are actual 'official' psychiatric diagnoses in that they can't be found in the Diagnostic and Statistical Manual (DSM). The DSM uses the term antisocial personality disorder (ASPD). Patients with antisocial personality disorder have difficulty with lying, impulsivity, repeated criminal acts, and impulsivity or irresponsibility. The majority of people with ASPD are not psychopaths. Psychopaths represent a minority of severely disordered people who lack emotional attachments or responsiveness. They are narcissistic and are unable to learn from experience. They lack empathy or remorse and are cold, cruel, callous people. This callousness is what distinguishes psychopathy from antisocial personality disorder.
There are a lot of people with antisocial personality disorder---about 3% of the United States population or nine million people. The exact prevalence of psychopathy may never be known because psychopaths usually only come to the attention of clinicians when they are caught committing crimes or when those around them coerce them into treatment. The most skillful psychopaths may not come to the attention of the law and may function successfully as politicians, religious leaders or heads of large corporations.
A screening tool for psychopathy was developed in the 1980's and has been widely used in research and forensic practice. Scores on the Hare Psychopathy Check List-Revised (PCLR-R) have been found to be useful for predicting violence and criminal recidivism. Psychopaths identified by the PCLR-R are being studied through functional neuroimaging in order to identify the physical basis for the disorder. These studies have shown that in psychopaths the part of the brain responsible for processing emotions works differently than in normal people. They also have different physiologic responses to emotion.
There is a genetic component to both ASPD and psychopathy as shown by adoption and twin studies. One large twin study has shown that for severe psychopaths as much as two-thirds of psychopathy can be attributed to genetics rather than environmental influences.
Can psychopaths be treated?
This is a tough question to answer. Psychopaths don't generally seek treatment voluntarily because they aren't bothered by their condition. They must be coerced into treatment or persuaded to participate by engaging their self-interest. For example, by emphasizing that treatment is a condition of parole and is necessary to stay out of jail or prison. Since psychopaths have difficulty learning from consequences, several treatment attempts may be necessary. The treatment must be designed to have open lines of communication between others involved in the psychopath's life in order to ensure truthfulness. There must be clear, consistent and firm boundaries between the patient and the therapist. Psychopaths with a high risk of violent behavior should only be treated in a secure and structured setting like a correctional facility. Psychopaths and people with ASPD are at increased risk of developing other psychiatric conditions such as mood disorders and substance abuse. Medication may be indicated for treatment of these co-existing conditions.
There is no evidence that psychopathy or ASPD can be cured. The goal of treatment is to minimize the impact of the conditions on others and on the patient. For example, one goal of treatment might be to minimize the risk of accidental injury by teaching the patient to recognize situations that trigger dangerous risk-taking behavior. Violence is another focus of treatment with psychopaths; violent behavior can be managed with administrative disciplinary procedures within the correctional facility or through the use of medication.
Specific treatment goals should be set up collaboratively with the patient so that expectations and treatment parameters are clear. The patient's self-identified treatment goal may also reveal his level of insight. When I asked one of my prisoners what he was working on in therapy, his answer was telling. "The truth," he said. "Telling the truth, it's something I've been working on for a while."
It's a beginning.