Comorbidity of personality disorders and substance dependence in treatment outcomes

Personality Disorders and Drug Disorders

One of the major problems facing social service providers is the fact that many clients experience multiple problems at one time. There is a particularly large amount of crossover between people with mental illness and addiction problems, because many mentally ill people attempt to self-medicate with drugs. Dealing with drug addiction and personality disorders at the same time can present its own particular set of problems, because active drug use needs to be ceased before one can determine whether medication is an appropriate intervention and the level of medication needed. However, the personality disorders can make a person more resistant to drug treatment; in fact, it may be almost impossible to treat someone's drug addiction without first addressing the underlying personality disorder.

Discussion

According to Teplin et al., substance dependence and personality disorders are highly prevalent comorbid conditions; though rates vary, it appears that approximately half of people with personality disorders may also suffer from substance dependence. (Teplin et al., 2004, p.516). There are different reasons that people with personality disorders might use substances. These reasons include: "diminishing or managing the symptoms of the personality disorder, enhancing self-esteem, decreasing feelings of guilt, managing negative affect, and amplifying feelings of diminished individuality. (Teplin et al., 2004, p.516). Moreover, they noted that substance abuse can make it more difficult to treat an underlying personality disorder. First, "Substance abuse by individuals with a comorbid personality disorder has been considered an indication of a greater personality disturbance," and predicts that therapy will be less successful. (Teplin et al., 2004, p.516). In addition, people with personality disorders appear more vulnerable to substance abuse issues than people without personality disorders. (Teplin et al., 2004, p.516). They also appear more vulnerable to full-blown addiction. In fact, because addiction is related to self-control, it makes sense that personality disorders marked by a lack of self-control would be linked to addiction.

While personality disorders generally precede substance abuse in people with comorbid conditions, the substance abuse can also precede the personality disorders. "Illicit substances can produce toxic effects on the brain and also reinforce regressive behavior, a combination that may result in a personality disorder secondary to substance dependence." (Teplin et al., 2004, p.517). The secondary personality disorders tend to be those with "narcissistic, antisocial, and histrionic characteristics." (Teplin et al., 2004, p.517).

Personality disorders are a good predictor for treatment success likelihood, because they provide good insight into whether or not a client is likely to comply with a treatment regime.

Individuals with personality disorders have "difficulty working cooperatively and collaboratively with service providers." (Teplin et al., 2004, p.517). Therefore, it should come as no surprise that one of the most treatment-resistance areas of substance abuse, opiate addiction, is thought to be highly correlated with personality disorders. (Teplin et al., 2004, p.517). To look at the correlation between opiate addiction and personality disorders, Teplin et. al examined outpatients at an office-based methadone maintenance program. They issued the patients the Millon Clinical Multiaxial Inventory (MCMI-III) to diagnose Axis II personality disorders, including both basic personality disorders and severe personality disorders. Their results supported the high comorbidity between opiate dependency and personality disorders. 77% of their subjects had at least one personality disorder:

Of those who had a personality disorder, 20% had two personality disorders, 14% had three personality disorders, and 6% had four personality disorders. Overall, depressive personality disorder was most commonly diagnosed (31%), followed by: dependent personality disorder (26%); masochistic (self-defeating) personality disorder (20%); antisocial personality disorder (17%); avoidant personality disorder (11%); schizoid and histrionic personality disorder (9%, respectively); borderline and sadistic personality disorder (6%, respectively); and narcissistic personality disorder (3%). It should be noted that the percentages add up to more than 100% because there is overlap among categories. (Teplin et al., 2004, p.519).

They were somewhat surprised by their results, which suggested lower rates of borderline and antisocial personality disorders than were expected. However, they suggested that there had been false positives in previous studies because "substance abuse can produce a syndrome that is diagnostically compatible with personality disorders. Characteristics of such a syndrome include low frustration tolerance, affect intolerance, impulsivity, and self-centredness, all of which can mimic a borderline and/or antisocial personality presentation." (Teplin et al., 2004, p.519).

Grant et al. looked at a broader range of substance abuse issues and personality disorders. They also looked at the relationship that gender had on those comorbidities. They used information obtained during the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), which was the largest comorbidity survey ever conducted, and was conducted by trained interviewers, and quality-controlled to assure test reliability (Grant et al., 2006, p. 122-123). However, this study used traditional DSM-IV diagnostic characteristics to identify persons with personality disorders. Moreover, the study purposefully excluded some personality disorders. This is because diagnosis of personality disorders requires evaluations of long-range functioning, and diagnosis of certain disorders, including borderline, schizotypal, and narcissistic personality disorders required a larger number of symptoms than the diagnosis of other personality disorders. (Grant et al., 2006, p. 123). Unfortunately, at least one of those disorders, borderline personality disorder, has previously been found to be very highly correlated with substance abuse issues.

The study found that the overall:

12-month prevalences of any alcohol use disorder and any drug use disorder were 8.5% and 2.0% respectively. Rates of abuse exceeded those for dependence for both alcohol and drug use disorders. The most prevalent PD in the general population was obsessive-compulsive PD (7.9%), followed by paranoid PD (4.4%), antisocial PD (3.6%), schizoid PD (3.1%), avoidant PD (2.4%), histrionic PD (1.8%), and dependent PD (0.5%). (Grant et al., 2006, p. 124).

Clearly, the results demonstrate that personality disorders are relatively rare. However, the results also demonstrate that personality disorders and substance abuse frequently overlap:

28.6% and 47.7% of respondents with a 12-month alcohol use disorder and drug use disorder, respectively, had at least one PD. Rates of any PD were greater among respondents with any drug abuse (37.8%) and any drug dependence (69.5%) than among respondents with alcohol abuse (19.8%) and alcohol dependence

39.5%). The prevalence of antisocial PD (12.3%), obsessive compulsive

PD (12.1%), and paranoid PD (10.2%) were the highest among respondents with an alcohol use disorder. These also were the most prevalent PDs among respondents with any drug use disorder, but the rates were much higher. The prevalence of specific PDs was much greater among respondents with dependence on alcohol (2.5%-18.3%) or drugs (10.1%-39.5%) compared with respondents with alcohol abuse (0.3%-9.5%) or any drug abuse (2.0%-22.3%). (Grant et al., 2006, p. 124-125).

The study did find gender differences in the correlation between personality disorders and substance disorders:

Similar to the pattern observed in the total sample, the associations between current alcohol and drug use disorders and PDs among men and women were overwhelmingly significant and positive, with the exception of the associations between avoidant, dependent, obsessivecompulsive, paranoid, and schizoid PDs and alcohol abuse. With respect to any drug use disorder, drug abuse, and drug dependence, associations remained the strongest for antisocial, histrionic, and dependent PDs among men and women. The same pattern was observed for any alcohol use disorder and alcohol dependence among men and women. Significant sex differences in the associations between alcohol and drug use disorders and PDs also were observed. The relationship between obsessivecompulsive (P

Conclusion

Both articles do a good job of explaining the relationship between personality disorders and substance disorders. The authors all did a good job of explaining the prior literature and why it suggests such a relationship. Furthermore, they did a good job of explaining why knowledge about comorbidities is important to those seeking to treat people with either substance disorders or personality disorders.

The articles were both written in an easy-to-read manner, which could be understood by anyone with at least a high-school education, even if they had no background in mental health. The articles also carefully explained the study methodology, so that the reader could form an independent assessment of the scientific merits of the study. However, there were some differences in the studies, which seem like they would impact their utility

First, the study by Grant et al. suffered from a serious weakness, in that it failed to examine borderline personality disorder. Prior research demonstrates that borderline personality disorder may be more highly linked to substance disorders than any other personality disorder, therefore it would seem important to include research regarding that disorder. However, the Grant study had a huge population, which made it easier to suggest that its results actually reflected the results one would find in the general population. Moreover, the researchers were careful to point out areas of weakness. The Grant study focused on gender differences, as well, which is important; women have been consistently overlooked in medical research, though it has been clearly established that women respond differently than men to the treatment of substance abuse disorders and personality disorders.

The study by Teplin et al. suffered from its own serious weakness. The sample size was relatively small, and consisted only of people who had been referred to the study. Therefore, it is likely that patients with overt symptoms of personality disorders were not referred to the study. However, by focusing on a specific addiction, the Teplin study was able to link specific behavior to specific personality disorders. Overall, this research would be more helpful to a practitioner, who has knowledge of the type of substance being abused, because it would help direct further screening for personality disorders.