Prevalence of Personality Disorders among Clients in Treatment for Addiction

Prevalence of Personality Disorders Among Clients in Treatment for Addiction 2 Louise Nadeau, PhD\ Michel Landry, PhD , Stephane Racine, MPs 3 This study determined the prevalence ofpersonality disorders among clients in treatmentfor addiction; this prevalence was compared with those found in similar studies and in clinical samples ofindividuals sufferingfrom other Axis I disorders. Our sample comprised 255 subjects. Thefirst edition ofthe Millon Clinical Multiaxial Inventory (MCMI) was used. Only 11.8% ofthe subjects did not score over 84 on any ofthe 11 Axis II scales. Over one-half had a score of 84 or higher on the passive-aggressive and dependent-personality scales. The mean number of scales in the 84+ category was 2.68. Comparisons show that this sample was more severe in most cases. (Can J Psychiatry 1999;44:592-596) Key Words: personality disorder, substance disorder, Millon Clinical Multiaxial Inventory, treatment, gender Objectives ersonality disorders (PDs) among clients with substance disorders (SDs) have been less studied than have Axis I disorders, but instruments that are valid and inexpensive to administer, such as the Millon Clinical Multiaxia1 Inventory (MCMI) (1) used in the present study, have allowed their prevalence to be documented. P This study determines the prevalence ofPDs among individuals admitted to public treatment centres in Quebec and compares these results with fmdings of similar studies and with those of clinical samples suffering from other Axis I disorders. Clinical studies have found that the proportion of individuals presenting both SDs and PDs varied from 53% to 100% (2-10). The most frequently diagnosed disorders are antisocial, borderline, narcissistic, and dependent personality disorders. The simultaneous presence of Axis I and II disorders increases the severity ofall disorders (11,12). In cases ofAxis II comorbidity, addiction can be successfully controlled in specialized treatment centres. However, the needs of these clients often exceed the capabilities of the services normally provided (13,14). There is an increased likelihood of premature termination and reduced effectiveness of treatment (15-17). For those who complete treatment, remission is comparable to that observed among those without PDs, although the level ofpsychological distress remains high (18). Method Our sample comprised 255 clients-182 men and 73 women-in 8 SD treatment centres in Quebec. The subjects were francophone and aged 18 years or over. The meanage was 34.5 years: 12% aged 18-24 years; 41% aged 25-34 years; 34% aged 35-44 years; and 13% aged 45 years or older. Testing took place after 7 days of treatment in order to exclude individuals suffering from acute withdrawal. Participation was voluntary, and all subjects signed a consentfonn. We compared our results with those of 5 studies (4,8,19-21) that had used the MCMI-I (Table 1). To better understand the specificity of SD, our results were also compared with those on clinical samples from Quebec. The first comprised 180 subjects treated for erectile ororgasmic disorders. The other 2 samples included individuals treated for sexual impulse problems at a medicolegal clinic: one comprised 44 men who had committed a rape or hadintrusive rape fantasies, and in the other were 87 men who had committed pedophilic acts. All subjects were francophone. All subjects signed a consent form. Manuscript received April 1998, revised, and accepted November 1998. 1Associate professor, Departernent de psychologie, Universite de Montreal, Montreal, Quebec. 2Director ofProfessional Services, Centre Dollard-Cormier, Montreal, Quebec. 3Scientist, Recherche et Intervention sur les Substances psychoactives - Quebec (RlSQ), Montreal, Quebec. Address for correspondence: Dr L Nadeau, Departement de psychologie, Universite de Montreal, CP 6128, succ « Centre-ville », Montreal, QC H3C We used the first edition ofthe MCMI (1), a self-reportinventory asking 175 true or false questions. Our results focused on the 11 personality scales (PSs) described in Table 2. The MCMI was translated into French (22). Based on 317 email: louise.nadeau.2@umontreal.ca Can) psychiatry, Vol 44, August 1999 592 August 1999 Personality Disorders and Addiction Table 1. Comparison of 5 studies that used the Millon Clinical Multiaxiallnventory (MCMI-I) Author N Diagnosis at admission Ness and others (20) 30 Opiate abuse or dependence Brown (19) 50 All substance dependencies 12-step treatment from 21-30 days detoxification After 21-30 days of treatment Craig and others (4) 86 Opiate abuse or dependence Detoxification After detoxification Craig and others (4) 107 Cocaine abuse Detoxification After detoxification Marsh and others (8) 159 Craig and others (21) Craig and others (21) Axis II No score + Schizoid Avoidant Type of treatment Time of testing After 48-72 hours of abstinence 593 MCMI validity index (1 or more on the Y scale); 9 were rejected because of exaggeration of symptoms (sum of scales 1 to 8 greater than 164); 6 were rejected because of missing data; 3 were rejected because the subjects were under age 18 years. In the other clinical samples, 25 tests (8%) were rejected. Statistical tests designed to compare means and proportions were used. The types oftests used are specified below. Differences between genders were calculated when the number of subjects allowed it. Results The first column of Table 2 shows the results by scale. Subjects are classified in this category for each scale on which their score is 84+. Only 11.8% did not score over 84 on any scale, over one-halfscored on the passive-aggressive (56.9%) 106 Alcohol abuse and dependent (52.9%) PS, and 0% scored on the compulsive or dependence PS. For the 74 cutoffpoint, the third column ofTable 2 shows 100 Opiate abuse or dependence 98.8% of subjects to be above this threshold. Over 50% scored on either the passiveaggressive, dependent, avoidant, borTable 2. Millon Clinical Multiaxial Inventory base rate scores derline, or schizoid PS. None scored By scale Highest score Average score more that 74 on the compulsive PS. Base rate score> 84 Base rate score> 74 Significantly more women than men Rank Rank Rank Rank % scored 84+ on the histrionic, schizo% % % typal, borderline, and paranoid PS. 11.8 0 11.8 1.2 U sing the 74 cutoff point, significant 3.1 70.61 33.3 4 5 5 8 52.5 gender differences remained only for 81.05 14.5 48.6 3 2 3 3 68.6 the histrionic and borderline PS. Opiate abuse or dependence Methadone treatment After admission to treatment 75.85 Dependent 52.9 2 69.4 2 21.2 Histrionic 10.6 9 24.7 8 2.7 Narcissistic 12.5 6 20.8 10 4.3 Antisocial 12.5 6 26.3 7 3.5 7 60.90 Compulsive 0.0 11 0.4 II 0.0 II 39.66 Passive-aggressive 56.9 20.8 2 82.30 Schizotypal 7.1 10 22.0 9 0.4 10 65.85 7 Borderline 21.2 5 55.3 4 3.9 6 75.45 4 Paranoid 12.5 6 31.4 6 4.7 4 69.05 6 Mixed 76.5 9.0 psychometric qualities (that is, internal consistency, testretestreliability, and discriminant validity), this translation is reliable and valid (23). Millon's taxonomy parallels that of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III). Base rate (BR) scores were computed for each scale. A BR Score of74 or more (74+) means that the subject shows signs of the disorder; a score of 84 or more (84+) signals prominenceofa disorder. Fifteen tests were rejected because of the 9 58.63 9 56.58 10 11 The fifth column of Table 2 presents the highest score obtained on a scale. Each subject is assigned to a single category. If the same score is obtained on 2 or more scales, the mixed category is used. Over one-fifth of subjects obtained their highest score on the passive-aggressive (20.8%) or the dependent (21.2%) PS. Comparisons by gender were performed using chi-square or Fisher's test when more than 20% of the cells contained less than 5 elements. Women were underrepresented on the passiveaggressive scale. In the seventh column of Table 2, mean scores are presented for each scale. Mean scores for the avoidant, dependent, passive-aggressive, and borderline PSs are all in the 74+ range. As shown in Table 3, comparisons by gender were made using t-tests. Women had a higher mean score than men on the borderline PS. For each subject, we summed the number of scales in the 84+ category. The mean number of scales was 2.68, with 71% of Vol 44, N06 The Canadian Journal of Psychiatry 594 Table 3. Mean score on personality scales by gender (substance abuse disorder, Quebec sample) Mean score (SO) Scale Male Female Total Schizoid 70.37 (23.44) 71.19 (25.59) 70.61 (24.03) Avoidant 81.04 (21.11) 81.10 (23.99) 81.05 (21.92) Dependent 75.34 (24.66) 77.15 (25.83) 75.85 (24.97) Histrionic 59.82 (19.23) 55.64 (28.70) 58.63 (22.38) Narcissistic 56.95 (21.29) 55.66 (24.92) 56.58 (22.35) Antisocial 61.68 (22.10) 58.96 (21.99) 60.90 (22.06) Compulsive 39.18 (18.02) 40.88 (21.85) 39.66 (19.16) Passive-aggressive 82.67 (23.36) 81.38 (25.30) 82.30 (23.89) Schizotypal 65.60 (11.16) 66.48 (14.14) 65.85 (12.07) Borderline" 73.57 (12.19) 80.12 (16.40) 75.45 (13.81) Paranoid 68.11 (12.96) 71.40 (16.31) 69.05 (14.05) "p < 0.01. borderline-our sample had the highest scores and, in most cases, they differed significantly from those ofother samples. Our sample had the lowest scores for the narcissistic andcompulsive scales. On 3 scales-histrionic, antisocial, and paranoid-our sample was close to the midpoint of the distribution. The mean BR scores and standard deviations of our sample were also compared with those of 3 other Quebec clinical samples. ANOVA and a Student-Newman-Keuls test were used. Our sample obtained higher scores on several scales (Table 4). These results also indicate that these 4 samples present different Axis II profiles. Discussion The MCMI is not a diagnostic instrument (24). It measures whether certain features have attained clinical significance. Our own test-retest reliability study (23) has shown that the intensity of symptoms decreases after a few weeks of treatment. All authors except Millon have reported similar results (25). Toxic effects of substances probably decrease after a few weeks of treatment (26). Table 4. Comparison of Millon Clinical Multiaxial Inventory scale score between 4 samples Alcohol and drug abuse Sexual dysfunction Rape Pedophilia Total (n = 255) (n = 173) (n = 34) (n=79) (n=54l) Schizoid 70.61 45.95- 61.50 61.77- 60.86 Avoidant 81.05 53.01- 70.50- 72.62- 70.19 Dependent 75.85 57.40- 67.15 76.38 69.48 Histrionic 58.63 55.08- 56.15 52.65 56.46 Narcissistic 56.58 63.35+ 60.41 57.53 59.12 Antisocial 60.90 66.55+ 67.38 59.56 62.92 Compulsive 39.66 60.14+ 51.29+ 51.63+ 48.69 Passive-aggressive 82.30 51.65- 63.94- 63.76- 68.64 Schizotypal 65.85 58.21- 62.09 65.29 63.09 Borderline 75.45 62.66- 67.12- 69.96- Paranoid 69.05 69.46 67.32 Axis II +This sample mean is significantly higher than the drug alcohol abuse sample. -This sample mean is significantly lower than the drug alcohol abuse sample. subjects scoring more than 84 on 1 scale. For the cutoff score of?4, the mean number of scales was 4.48, with 95% of subjects scoring at least 1 scale. The Mann-Whitney U nonparametric test was used to make comparisons by gender, since this variable is not continuous. On average, women scored 84+ on 3.08 scales, compared with 2.52 scales for men (U = 5614.5, P = 0.05). There was no statistically significant difference for the 74 cutoff point. Our results were compared with those of 8 samples mentioned in Table 1. t- Tests showed that for 6 scales-schizoid, avoidant, dependent, passive-aggressive, schizotypal, and Our results reveal relatively severe personality disorganization in the upper range, compared with other studies with addicted clients. These results confirm that no single PD is typical ofall addicts (27). However, these comparisons are subject to limitations. The length oftime between admission to treatment and test completion may have varied from one study to another. Particular psychosocial characteristics of the different samples may have influenced the results. The comparison with 3 Quebec clinical samples confirms the more 69.68 69.16 severe Axis II features of our sample. These findings are consistent with the results of a previousstudy (28) in 3 rehabilitation centres using a validated French version of the Addiction Severity Index (29), which found greater deterioration of the psychological, family, and legal spheres in Quebec samples than in those from outside Quebec. The consistency confirms the validity of the 2 instruments and also hints about the links between Axis I and II disorders. 70.04 Results concerning the passive-aggressive PS ofthe MCMI-I should be interpreted with caution. Several clinicians noted, as we did, that its high scores suggest an overlap with SD. In the DSM-IV, the passive-aggressive PD has been relegated to August 1999 Personality Disorders and Addiction an annex because of doubts as to its specificity. Millon excluded this scale from the MCMI-III. Clinical Implications Results according to gender show that PDs are more prevalent among women, no matter how the results are analyzed. Numerous studies have demonstrated similar results (30). Women, however, have as good a prognosis as men and, in some cases, a better one (31). The specific effect of PD on treatment outcome in reference to gender, however, is unknown. • The prevalence ofAxis II disorders is high among clients with an addiction. • Axis II disorders should be given as much attention as Axis I disorders. • Those in charge of treatment programs should examine how best to adapt their services to deal with Axis II comorbidity. Limitations SDs and Axis II disorders must be treated concurrently (10,32,33). Those in charge oftreatment programs should examine how best to adapt their services to deal with Axis II comorbidity. • The Millon Clinical Multiaxial Inventory (MCMI) is not a diagnostic instrument. • The intensity of Axis II disorders decreases after a few weeks of treatment for clients with substance disorders. • Results concerning the passive-aggressive personality scale on the MCMC-I should be interpreted with caution. Acknowledgements This research was supported by a grant from the Conseil quebecois de la recherche sociale to the team Recherche et Intervention sur les Substances psychoactives - Quebec (RISQ). 17. 18. References I. 2. 3. 4. 5. 6. 7. 8. 9. 10. II. 12. 13. 14. 15. 16. Millon T. Millon Clinical Muitiaxial Inventory. Minneapolis (MN): National Computer Systems; 1983. Calsyn DA, Saxon AJ. Personality disorder subtypes among cocaine and opioid addicts using the Millon Clinical Multiaxial Inventory. International Journal of the Addictions 1990;25:1037--49. Craig RJ. 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Exploring the meanings of substance abuse: an important dimension of early work with borderline patients. Am J Psychother 1990;44:61-7. 596 The Canadian}ournal of Psychiatry Vol 44,No6 Resume Cette etude a determine la prevalence des troubles de personnalite parmi les clients en traitement pour toxicomanie ,. cette prevalence a he comparee acelles constatees dans des etudes semblables et dans des echantillons cliniquesdepersonnes souffrant d'autres troubles de I'axe I. Notre echantillon se composait de 255 sujets. Lapremiere editionde I 'Inventaire clinique multiaxial de Millon (MCMI)a ete utilisee. Seulement 11,8 % dessujets n 'ont pas obtenu de resultat superieur a84 aaucune des 11 echelles de l'axe II. Le nombre moyen d'echelles dans la categorie des 84 et plus etait 2,68. Les comparaisons indiquent que cet echantillon etait plus gravement malade dans la plupart des cas.