Personality disorders are entrenched patterns of thought and behavior that damage affected individuals\u2019 ability to do such things as maintain friendships or relationships, maintain a productive daily routine or take advantage of social opportunities. The American Psychiatric Association gives doctors the freedom to diagnose 10 main forms of these disorders. In a study published in January 2014 in the journal Addictive Behaviors, a Belgian research team assessed the impact of various personality disorders on the chances that a person will successfully complete an opioid addiction treatment program that uses an oral medication called naltrexone. Personality Disorder Basics Personality disorders get their name because they involve longstanding personality traits that typically remain in effect once they\u2019re established. The 10 diagnosable disorders in the U.S. are schizoid personality disorder, paranoid personality disorder, schizotypal personality disorder, histrionic personality disorder, antisocial personality disorder, narcissistic personality disorder, borderline personality disorder, obsessive-compulsive personality disorder, avoidant personality disorder and dependent personality disorder. These conditions are grouped together into one of three clusters (called Cluster A, Cluster B and Cluster C) based on the relative similarity of their core symptoms. Depending on the individual, a case of any given personality disorder can range in impact from mildly debilitating to highly debilitating. In many cases, affected individuals lack any real awareness of how their problems damage or restrict them in day-to-day life. Since long-term personality traits only fully emerge in adulthood, doctors usually don\u2019t diagnose personality disorders in teenagers or younger children. Naltrexone Basics Naltrexone is useful in opioid addiction treatment because it essentially blocks opioid substances from producing the changes in brain chemistry that foster the development or continuation of addiction. Because the medication has a rapid effect, doctors can only safely use it in people who have already stopped using opioids. If a current opioid user takes naltrexone, he or she can develop particularly intense symptoms of opioid withdrawal. Some treatment programs use an implanted form of the medication that produces its benefits gradually over time. However, most programs use daily oral doses of naltrexone. Because of its narrow focus on blocking the brain effects of opioids, naltrexone must be combined with other treatments (including psychotherapy or support group participation) as part of a larger overall approach to addressing opioid addiction. Impact of Personality Disorders In the study published in Addictive Behaviors, researchers from Belgium\u2019s Free University of Brussels assessed the impact of personality disorders on the effectiveness of oral naltrexone treatment in opioid addiction programs. They performed this assessment with the help of 30 adults who had completed the initial detoxification stage of addiction recovery. All of these individuals took part in testing designed to identify their general personality characteristics, as well as specific symptoms of the various personality disorders. After completing these psychological evaluations, the researchers created what they called \u201cpersonality profiles\u201d for each participant. All 30 adults were prescribed oral naltrexone after completing detoxification and asked to keep using the medication for at least six months. Rates for regular oral naltrexone use varied among the study participants. Some of these individuals rarely or never missed their daily doses of the medication, even over periods of treatment that lasted longer than six months. Others only occasionally took the medication as prescribed over a period of time that lasted anywhere from three to six months. Still others never took their prescribed naltrexone doses after completing opioid detoxification. When the researchers compared the personality profiles of these three groups, they found clear indications of the impact of personality disorders. The members of the group that consistently took naltrexone had only a couple of mild personality problems, including fairly subdued symptoms of antisocial personality disorder. The members of the group that occasionally took their medication had an average of nine personality problems, including fairly pronounced symptoms of antisocial personality disorder and paranoid personality disorder. The members of the group that never took their prescribed naltrexone treatment had an average of 12 personality problems, including pronounced symptoms of antisocial personality disorder and narcissistic personality disorder. Significance and Considerations As a result of their findings, the authors of the study published in Addictive Behaviors believe that the symptoms of personality disorders can have a sharply negative effect on the long-term success of opioid addiction treatment programs that use oral naltrexone. However, they also believe that doctors can help offset this negative effect by tailoring their choice of addiction treatments to the personality characteristics of each individual patient.