Alcohol abuse and dependence are among the most prevalent mental disorders in the general population. According to a nationally representative sample survey of youth and adults in Spain, alcohol abuse has affected about 7-10% (roughly 3 million peoplet) of the population (Echeburúa et al., 2005). Nearly half of them will become alcoholics in the near future. This problem obviously is a significant public health challenge.
In spite of growing interest in alcohol related issues, it remains difficult to accurately define the relationship between personality disorders. (PDs) and alcohol dependence. The reported prevalence of PDs in alcoholics ranges from as low as 22-40% (Zimmerman an Coryell, 1989; Powell and Peveler, 1996; Driessen et al., 1998; Pettinati et al., 1999; Grant et al., 2004) to as high as 58-78% (DeJong et al., 1993; Nurnberg et al., 1993; Morgenstern et al., 1997; Fernández-Montalvo et al., 2002). A meaningful comparizon of prior and more current data in reported prevalence studies is difficult to make because of large discrepancies.
Similarly, the number and typez of PDs found in the literature are very heterogeneous. The most prevalent in the clinical trials have been dependent and histrionic (DeJong et al., 1993; Grant et al., 2004); dependent, paranoid and obsessive- compulsive (Echeburúa et al., 2005); paranoid (Nurnberg et al., 1993); borderline (Powell and Peveler, 1996); antisocial (Grant et al., 2004; Morgenstern et al., 1997); narcissistic and avoidant (Pettinati el al., 1999); and avoidant and borderline (Fernández-Montalvo et al., 2006). Thus, the available current data are inconsistent and not conclusive. Furthermore, the average number of PD diagnoses is generally 1.8-4 with an extensive overlap among PDs themselves (Driessen et al., 1998; DeJong et al., 1993).
The diagnostic disparity and the lack of consistency in the literature with respect to the prevalence, the number and the types of PDs associated with alcohol depencence are likely related to the assessment tools (questionnaires, interviews, etc) to the severity of alcoholismo considered (abuse or dependence) and to the mental health settings (impatients or outpatients) (Sher et al., 1999).
In a prior exploratory study with a quite small sample, PD diagnoses were analysed in a sample of male alcoholics (Echeburúa et al., 2005). Extending this area of research with a larger sample size of male and female patients, the main aims of this study were, first, to find out if the frequency and profile of PDs among treatment-seeking alcoholics were diferent from normal population and from non-addicted patients who sought treatment for another Axis I mental disorder. Second, to compare the concordance between two well-known tools for assessment of PDs: a semi-structured diagnostic interview (Intenational Personality Disorders Examination, IPDE) (Loranger, 1995) and a self-report (Millon Clinical Multiaxial Inventory, MCMI-II) (Millon, 1997). Our main hypothesis is that PDs are more prevalent among alcoholics than among other diagnostic groups or among the general population.

Participants

The sample for this cross-sectional clinical-epidemiological study consisted of 381 subjects (158 alcohol-dependent subjects, 120 clinical patient affected by mental disorders other than addictions and psychosis and 103 normal subjects from the general population). This sample did not include the patients and subjects described in our previous exploratory study (Echeburúa et al., 2005).
All patients were drawn from attenders at the psychiatric outpatient clinic of the Psycho-organic Medicine Clinic (Bilbao, Basque Country, Spain). Normal subjects were found among workers at a university (clerks; N = 46) and in a canning factory (N = 57). The most significant demographic characteristics of the total sample are presented in Table 1. Patients and non-patients gave their informed consent to take part in the study, and the response rate was 100%.
The alcohol-dependent group (N=158) was recruited from consecutive attenders >18 years of age who met the diagnostic criteria of DSM-IV-TR (American Psychiatric Association, 2000) for alcohol dependence. All of them were seeking treatment for problems related to drinking. A primary diagnostic of alcohol dependence was required to be included in the clinical trial.
The clinical "control" group (N=120), also >18 years of age, was chosen consecutively from non-addicted subjects seekin treatment for varius mental disorders, such as major depression, generalized anxiety disorder, panic disorder and adaptive disorder.
The normative group (N=103) was made up of people without Axis I mental disorders, who were encouraged to participate in this study by giving them feedback on their personality test results. The participants were selected to match the clinical groups in terms of age, gender and social class, the clinical groups having by chance turned out to be reasonably matched on these measures.

Assessment measures

The Structures Clinical Interview is used to assess, in an initial interview, mental disorders according to diagnostic criteria of DSM-IV-TR. The content of the interview is related to the information most relevant to this study: current difficulties, current mental disorders, antecedents, family, education, work, social relationships, alcohol and drug abuse, hobbies, etc.
Two personality assessment tools were used. The MCMI-II (Millon, 1997; TEA, 2000) is a self-report questionnarie with 175 true/false items. Thirteen clinical scales assess personality patterns thar relate to DSM.III-R Axis II disorders. There are ten clinic personality pattern scales (schizoid, avoidant, dependent, histrionic, narcissistic, antisocial, aggressive-sadistic, compulsive, passive-aggressive and self-defeating), as well as three severe personality pathology scales (schizotypal, borderline and paranoid).
Raw scores on scales were weighted and converted to base rate scores. The base rate scores reflect the prevalence of a particular PD. According to the conservative criteria of Weltzler (1980), a base rate score >84 is considered to be significant. Although the MCMI-II offers good internal consistency, it has only moderate accuracy for assigning patients to diagnostic groups across a variety of clinical criteria.
The IPDE (Loranger, 1995; López-Ibor et al., 1996) is a semi-structured diagnostic interview designed to assess PDs. The IPDE covers all criteria for the 11 Axis II disorders of DSM-IV. In order to establish reliable diagnoses, the behaviour or trait must be present for al least 5 years and the criterion must be met before the age of 25 years. A self-administered IPDE screening questionnaire is available before the interview to assist in identifying PDs that might be of focus in the interview. Inter-rater reliability of the IPDE (median kappa =0,73), as well as test-retest reliability (mediam = 0,87= (Blanchard and Brown, 1998), is generally good.

Procedure

Once all participants were selected according to the previously indicated criteria, the pre-treatment assessment was conducted in two sessions. In the first session, data related to psychopathological characteristics were collected and the MCMI-II and the IPDE screening test were carried out. In the second session, the PDs identified in the previous IPDE screening test were accurately assessed with the IPDE interview. The time between assessments was 1 week. Alcohol-dependent patients were abstinent before the first interview for al least 2 weeks. All assessments were made between 2003 and 2006.

In order to control the inter-rater reliability, a clinical psychologist (the second author) and a psychiatrist (the third author) sat in on the same interview and provided independent ratings for each subject. Using the structured clinical interview and the IPDE, they were able to give a clinical diagnosis of both alcohol dependence/other mental disorders and PDs. The degree of agreement between the professionals, with respect to the diagnosis of alcoholism/other mental disorders, was 100%. The inter-rater reliability for PDs in the joint interview was quite high (kappa = 0,81).

In this study, the following data were analysed: (i) the overall prevalence rate of PDs among the different samples; (ii) the PDs profile among the different groups.

Parametric (t-test and ANOVA) and non-parametric tests were used for statistical analysis. All comparisons between groups were analysed using the Kruskal-Wallis H-test. The Mann-Whitney U-test was used as a post-hoc procedure.

Prevalence rates of Axis I diagnoses, with a duration of at least 3 months, are given for both the clinical samples in Table 2. GAF scores mean was 43.97 (SD = 7.48) for the experimental group and 45.35 (SD = 6.70) for the clinical group, with no significant statistical differences (t=0.112).

Prevalence rates of PDs are reported with respect to both instrument and, in addition, the "combined" rates. According to this last criterion, 44,3% of the clinical sample of alcoholics and 21.7 % of the general clinical sample (vs 6.8% of the normative sample) showed at least one PD. A comparison between groups in the overall prevalence rate of PDs showed statistically significant differences (X²=46.904, df = 2; P<0.0001). PDs were more frequently diagnoses in alcoholics than in the other groups (Table 3).

The most prevalent PDs, among the alcoholics, were obsessive-compulsive PD (12%), followed by antisocial, paranoid and dependent PDs (7% each), narcissistec (6,3%) and finally borderline and histrionic PDs (5.1% each). In comparison, the most frequently diagnosed PDs among the non-addicted patients were obsessive-compulsive PD (9.2%), dependent PD (6.7%), followed by paranoid PD (4.2%). Lastly, in the normative control group, the most prevalent PDs were obssesive-compulsive and histrionic PD (1.9% each). There were statistically significant differences among the different groups. Antisocial, borderline, histrionic and narcissistic PDs were more associated to alcohol-dependent subjects than to any other group (Table 4).

With respect to the three clusters of PDs, the presence of cluster B and C was higher among the alcoholics (N=30), 19%; N=34, 21,5%, respectively) than in the clinical group (N=5, 4.2%; N=16, 13.3%) and in the normative group (N=3, 2.9%; N=3, 2.9%). These differences were statistically significant (X²>=24.523, df=2; P<0.0001; x²=18.074, df=2; P<0.0001).

Regarding the number of PDs shown by individual patients, one PD was the most frequent. There were only 24 patients, in both clinical groups (9%) and none in the normative control group who showed two or more PDs. There were statistically significant differences between the clinical and the normative groups (x²=52.461, df=2; P<0.0001).

The concordance between the IPDE and the MCMI-II to assess PDs was very low in both clinical groups (kappa=0.133) in alcohol-dependent subjects group; kappa=0.082 in clinical controls) and in the normative group (kappa=0,069).

A strength of our design was the inclusion of both a clinical control group and a normative control group and the diagnosis of PDs with two specific asssessment tools (MCMI-II and IPDE), even though the diagnostic approaches are not exactly the same. In addition both categorical and dimensional approaches for PDs were considered. These features distinguish this study from much of the previous literature.

One limitation in this study is that a different result might be found in a sample of alcohol-dependent people drawn from the general population. In addition, the participants only represented the alcohol-dependent patients in outpatient treatment. This study does not deal with the homeless or people belonging to a lower class with many psychosocial problems (no job, no partnership, no home, etc) who in Spain tend to underutilize health care resources. This study relates to more integrated patients, though it includes some with severe alcohol dependence. The advantage of this approach is thar it is possible to study alcoholism in itself, independently from social deprivation.

The most salient findins is that 44.4% of the alcoholics met IPDE + MCMI-II diagnostic criteria for a PD compared to 21.7% of the non-addicted patients and 6.8% of the normative controls. Previous studies found that PDs were very common in alcoholics (DeJong et al., 1993; Numberg et al., 1993; Powell and Peveler, 1996; Morgenstern et al., 1997; Driessen et al., 1998; Pettinati et al., 1999; Grant et al., 2004; Fernández-Montalvo et al., 2006). The contribution in this study is in showing that the high rate of comorbidity with PDs is different from and much higher in alcohol dependence than in other Axis I mental disorders, such as mood and anxiety disorders.

With respect to the types of PDs, the most prevalent PD in all groups was obsessive-compulsive. Antisocial, borderline, histrionic and narcissistic PDs were more associated to alcohol-dependent subjects than to other groups. Unlike other studies, where the average number of PD diagnoses is generally 2-4 (DeJong et al., 1993; Driessen et al., 1998), the average number of diagnosed PDs for each subject in our study was one.

These findings are consistent with those found by other studies (Driessen et al., 1998; Fernández-Montalvo et al.,2006), but not with others, in which the prevalence rates of PDs in alcoholics were higher (Nurnberg et al., 1993; DeJong et al., 1993). The lack of consistency with our study findings could be related to our sample (drawn only from outpatients) or to the different assessment tools (IPDE and MCMI-II together) used in our study to diagnose a PD. The accuracy of the self-reports, such as MCMI, by themselves can be expected to be poor, the kappa index between both instruments showing a very low concordance, according to other studies (Fernández-Montalvo et al., 2006).

The main difference between alcoholics and non-addicted patients showed nearly three times more PDs than the subjects of the normative control group. With respect to the clusters of PDs, the presence of clusters B and C was higher ammong alcoholics than in the clinical and normative groups.

These new findings validate our approach in the previous pilot study (Echeburúa et al., 2005), but also are slightly different. In both studies, there was a high comorbidity of alcohol dependence with PDs (about 40-4%), which was much higher than in other Axis I mental disorders, and the average number of diagnosed PDs for each subject was one. The main difference of this study with the presented data in our 2005 paper is that now, with a much larger sample, we were able to point out PDs specifically associated to alcohol-dependent subjects. That was not possible in our previous study, restricted to a quite small sample of only male alcoholics.

Further research should take into account other relevant variables related to alcohol dependence. These specific instruments (IPDE and MCMI) do not detect features of the patients who are related to alcohol dependence. That is the case, for example, of interpersonal relationships, which are often damaged due to drinking among patients who had previously good relationships. Structured interview should pay attention to this relevant area.

This study has both theoretical and applied implications. The accurate understanding of PDs in alcoholics could help to guide further research regarding treatment decisions according to the patient's personality pattern. Dimensional approaches to PD diagnosis could yield more accurate information (Ullrich et al., 2001). And, finally, specific gender differences should be dealt with in further research in order to test some preliminary conclusions (obsessive-compulsive, histrionic, schizoid and antisocial PDs, more frequent in alcoholic women; dependence, more frequent in alcohol-dependent men) (Grant et al., 2004).

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