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Personality disorder, depression and functioning: Results from

the ODIN study.

Patricia Casey1 , Gail Birbeck, Catherine McDonagh,

Ann Horgan, Chris Dowrick, Odd Dalgard, Ville

Lethinen, Jose-Luis Ayuso-Mateos, Graham Dunn,

Helen Page, Claire Wilkinson, Greg Wilkinson, Jose-

Luis Vasquez-Barquerez and the ODIN Group*

* Andres Arriaga, Lourdes Aznar, Trygve Borve, Alfonso de la Calle, Maria Carnicero,

Emma del Castillo, Graham Dunn, Mette Finne, Fiona Ford, Clare Hayes, Andres Herran,

Fiona Johnstone, Nicola Jones, Tarja Koffert, Marja Lehtilä, Erin, Michalak, Christine

Murphy, Anne Navra, Teija Nummelin, Armando Oviedo, Helen Page, Helena Rasi-

Hakala and Britta Sohlman

1 Address for Correspondence: University College Dublin Dept. of Psychiatry,

Mater Misericordiae Hospital, Dublin 7, Ireland.

Tel. 00-353-1-8032176. Fax. 00-353-1-8309323.

Email: apsych@mater.ie

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ABSTRACT

Background: There is little information of the prevalence of personality disorder (PD) in

those with depressive disorder in community samples; neither is there any data on the

impact of PD on service utilisation or outcome in this setting.

Methods: A two stage screening study to identify cases of depressive disorder using

SCAN in 5 European countries. Personality assessed 6 months after the diagnostic

interview. Follow-up for one year using symptom and social function measures.

Results: Personality disorder is present in 22% of a community sample with depressive

disorders but the range varied from 13.7% to 33.3% across countries. Cluster C formed

43% of the total. Long-term psychotropic drug use was more common in the PD group

even after depression was controlled. Those with PD had higher symptom scores at the

outset and although the PD group were more likely to be cases at follow-up, this

disappeared when the depression score was co-varied. Only initial social function

predicted outcome at 6 and 12 months.

Limitations: The use of a non-treatment seeking population may limit the application of

the findings to clinical populations.

Conclusions: PD is common even in a non-treatment seeking population with depressive

disorder. It impacts upon outcome at 6 and 12 months but this is related to the initial

severity of depressed mood. Social function is the only independent predictor of outcome

and should be assessed separately.

Key Words: Personality disorder. Social function. Depressive disorders. Community.

Outcome.

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PERSONALITY DISORDER, DEPRESSION and FUNCTIONING: Results from

the ODIN study.

Depressive disorders and personality disorder are often co-morbid although the strength

of this association varies with the treatment setting. For example, in primary care 25% of

those with depressive disorders were co-morbid for personality disorder (Casey et al

1990; Patience et al 1995) and among psychiatric out-patient attendees this co-morbidity

is even greater (Corruble et al 1996) There is agreement that the presence of a personality

disorder has an adverse effect on the outcome of, and GP service utilization by, those

with axis 1 disorders (Patience et al 1995; Moran et al 2001), although this view has

recently been challenged (Mulder et al 2002).

Little attention has been directed to those in the community with depressive disorders and

co-morbid personality disorder and those studies that have incorporated evaluation of

personality have limited it to the antisocial category (Jenkins et al 1997; Kessler et al

1994). It is therefore unclear if the adverse effect of co-morbid axis 1 and axis 2

diagnoses is similar in community and in clinical settings.

The study reported here is part of a larger two stage screening study of depressive

disorders, the Outcome of Depression International Network (ODIN). Conducted in 5

European countries, the overall aim was to evaluate the prevalence and outcome of

depressive disorders in the general population.

The aim of the present paper is to report the national trends in the 5 participating

countries of co-morbid personality and depressive disorders. It also examines the impact

of PD on the severity of depressive disorders, on social functioning, medication and

service utilization and on functional and symptomatic outcome.

We tested the hypotheses that depressive disorder when co-morbid with personality

disorder would be associated with greater symptomatic severity and functional

incapacity, and with greater use of the primary care services and psychotropic medication

when compared to those with depressive disorder alone.

Methods

The methods for this study have been described in detail elsewhere (Dowrick et al 1998)

but will be summarised here for clarity.

Screening, diagnosis and risk factors: Adults aged between 18 and 64 were selected from

the census register in urban and rural sites in Ireland, Britain, Norway, Finland, and from

an urban site only in Spain. The sample was screened for depressive disorder using the

Beck Depression Inventory (BDI) (Beck et al 1961). Those scoring above the cut-off of

13 were then offered a diagnostic interview, using the Schedule for Clinical Assessment

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in Neuropsychiatry (SCAN)(WHO 1994). The ICD-10 (WHO 1992) diagnoses of

interest were single and recurrent depressive episodes, bipolar and persistent mood

disorders and adjustment disorder with depressive features. All SCAN cases were re-

assessed 6 and 12 months after the initial diagnostic interview.

Possible risk factors for these disorders were examined including social supports using

the method of Dalgard et al (1995) and life events using the List of Life Threatening

Experiences (Brugha et al 1985). Health service and medication use was measured using

the Client Service Receipt Inventory (Knapp and Beecham 1993).

Personality Assessment: Personality was assessed using the Personality Assessment

Schedule (PAS) (Tyrer and Alexander 1979). Only those who were SCAN positive for

any depressive disorder were assessed and this took place at the time of the 2nd

. SCAN

interview since a sizeable proportion would have recovered by then, minimising the

possibility of contamination by axis 1 symptoms.

The PAS is a structured interview in which 24 personality traits are rated on a 9-point.

Scale. A computer programme generates a categorical diagnosis for ICD-10 (1992).

Questions in the schedule are framed so that constant reference is made to pre-morbid

traits. Behavioural examples, noticeable to those outside the person’s immediate circle of

friends/family, are required to confirm the trait abnormality and these must be consistent

in a variety of settings prior to the onset of any axis 1 episode.

Social Function Schedule: Social function was measured using the Social Functioning

Schedule (SFS) (Remington and Tyrer 1979). The interview takes about 15 minutes and

twelve areas of functioning are assessed on a visual analogue scale, covering the previous

month and generating a score from 0 to 100 with a high score indicates impairment.

Training and Quality Assurance: All interviewers were trained in the use of the PAS by

one of the authors (PC) who had extensive experience in its use. This consisted of scoring

videotaped interviews prepared by one of the authors of the schedule (PT) followed by a

refresher course just before the personality evaluation commenced.

Statistical analysis: Data was analysed using SPSS for windows (8.0). Since the vast

majority of the patients providing date (297 out of 302) were initially from the screen

positive sample, sampling weights were not used in the analyses reported in this paper.

Results

Descriptive data

Three hundred and two people with depressive disorders were interviewed of whom 55

(22%) had personality disorder although it is clear from table 1 that there is wide

variation between countries, the proportion being highest in Spain and lowest in Britain.

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Table 1 near here

Table 2 shows the demographic breakdown as well as the employment status of those

with and without personality disorder.

Table 2 near here

Symptoms and social functioning

The mean BDI and social functioning scores of those depressives with and without

personality disorder as well as their trajectory over the one year follow -up period are

shown in figure 2.

Figure 1 (a and b) near here

Only the BDI score at time 1 is significantly higher for the personality disorder group.

Neither social function nor the BDI score at any other time point differs between the

personality disorder groups.

Treatment and Outcome

The effect of personality disorder on referral to psychiatric services at any time during the

study period, as well as antidepressant prescribing and psychotropic medication use is

shown in table 4 and a few significant findings emerge; the use of psychotropic

medication at first assessment is significantly higher in those with personality disorder

although this disappears when co-varied for severity of depression. The use of

psychotropic medication at one year follow-up is also significantly higher in the

personality disordered group and this remains even after co-varying for severity of

depression.

Table 3 near here

Those with personality disorder were also more likely to be “cases” at 6-month follow-up

but this no longer pertains when the severity of depression is co-varied. Logistic

regression analysis was used to evaluate the factors influencing the outcome at 6 months

and one year.

Table 4 near here

At 6 month follow-up life events, severity of depression and social functioning at time 1,

all contributed significantly to caseness, but by one year neither life events nor depression

severity at time 1 were significant and only social functioning continued to significantly

influence outcome. In view of the recognised relationship between personality disorder

and social function the possibility of an interaction between personality disorder and

social functioning in determining “caseness” at follow-up was explored but none

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emerged either at 6 month (OR 0.79, CI 0.54-1.16) or 1 year follow-up (OR 1.05, CI

0.69-1.61).

Discussion

There are a number of methodological issues relating to the study methods that are worth

examining. Firstly, the population under study is one that is not seeking treatment having

been recruited by a two-stage screening process. The relevance of the findings to clinical

populations is therefore open to question.

The issue of contamination of personality by depressive perspective is one that is also a

cause of concern. By using an interview schedule that constantly refers to the pre-morbid

state and by conducting the interviews at the 6 month follow-up point when 50% of

subjects were no longer SCAN cases, it was hoped to minimize this problem.

Finally the sample size is small in some of the sites, notwithstanding the large number

who were screened. Where sample size is believed to compromise the generalisability

this is stated in the text. Consideration was given to evaluating personality in a sample of

non-depressed subjects as this would have provided information on the frequency of

personality disorder in the community and on the role of personality disorder in the

aetiology of depressive disorders but funding and time constraints prevented this.

Descriptive data

Our study is unique in that it is the first to examine the impact of the totality of

personality disorders on a community sample with depression although comparison with

other studies is, by implication, limited.

Studies of personality disorder in the general population have found a prevalence of

between 5.9 and 13.4% (Samuels et al 1994; Torgersen et al 2001) and among primary

care attendees with depressive illness over 25% have co-morbid personality disorder

(Patience et al 1995; Casey and Tyrer 1990). Our finding of an overall prevalence of 22%

for co-morbid PD in this study of community depressives is therefore not unexpected,

lying between the figure obtained for the general population and primary care attendee.

The figure for Spain is much higher than that of any other country and must be

interpreted with caution in view of the small sample size and wide confidence intervals.

Other explanations for the variation in prevalence between countries, and not answerable

using the present methodology, include cultural differences in admitting to abnormal

personality traits.

The demographic data is of some interest since we found no gender, age or urban/rural or

employment status differences. As there have been no previous studies among those with

depressive disorders in the general population that included all categories of PD it is not

possible to comment further since studies that have identified differences have been

carried on the general rather than depressed community samples (Blazer et al 1985).

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Symptoms and functioning

Surprisingly social functioning did not distinguish the personality disordered from the

non-personality disordered depressives possibly due to the different impact personality

has on functioning in a sample from the general population or alternatively due to the

differing social impact that depressive disorders have on those in a population not

seeking treatment, since social dysfunction is one factor associated with referral to the

specialist services (Casey et al 1985). Our results point to the possibility that personality

disorder “behaves” differently with regard to depression in community settings and this is

supported by the finding that speed of recovery was no different between those with and

without personality disorder, differing from the findings of studies conducted in clinical

settings (Patience et al 1995; Casey et al 1996) in which recovery is slower in the former.

Treatment and Service Impact

Our findings that personality disorder did not increase referral to the psychiatric services

differs from other studies in primary care (Moran et al 2001) and again is probably due to

the present sample being one that is not actively seeking treatment. We have however

replicated the findings of others that greater use of short-term psychotropic medication in

those with personality disorder was dependent on depression severity (Moran et al 2001;

Rendu et al 2002) but that long-term use was independent of depression severity. This

highlights the importance of assessing personality in those with mood disorders in view

of the hazards of long-term medication use.

Outcome

Univariate analysis confirmed the findings of others (Patience et al 1995; Tyrer et al

1990) that the short- term outcome of depression is worse in those with personality

disorder due to the greater severity of depressed mood in this group. In multivariate

analysis personality disorder did not emerge as influencing outcome either at 6 months or

1 year, a finding supporting the results of a recent meta-analysis (Mulder 2002). However

initial social functioning did predict outcome, highlighting the importance of conducting

such an evaluation. The failure to find an interaction with personality disorder

demonstrates that in a community population social function is not a proxy measure for

personality disorder.

In conclusion, this study highlights the importance of personality disorder in relation to

several aspects of depressive disorders, particularly psychotropic medication use.

However, social functioning is much more important in determining outcome and this is

independent of personality disorder.

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Acknowledgements

ODIN has received financial support from: the European Commission Biomed 2

Programme (Contract BMH-4-CT96-1681); English National Health Service Executive

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North West Research and Development Office (contract RDO/18/31); Spanish F.I.S. (Exp

No 96/1798); Welsh Office of Research and Development (Contract RC092); grants from

the Norwegian Research Council, Council for Mental Health and Department of Health and

Social Welfare; the Finnish Pensions Institute of Agricultural Entrepreneurs (Contract

0339); and grants from the University Central Hospital of Turku.

___________________

PATRICIA CASEY, FRCPsych., MD., University College Dublin Dept. of Psychiatry,

Mater Misericordiae Hospital, Dublin 7, Ireland; BIRBECK, GAIL, National Research

Agency, The Penthouse, Bracken Court, Bracken Rd., Dublin 18, Ireland; CATHERINE

McDONAGH, St. Davnet’s Hospital, Monaghan, Ireland; ANN HORGAN, Tralee General

Hospital, Co. Kerry, Ireland; CHRISTOPHER DOWRICK, M.D., Department of Primary

Care, University of Liverpool; UK ODD STEFFEN DALGARD, M.D., University of Oslo,

Norway; VILLE LEHTINEN, M.D., STAKES, Mental Health Unit, Turku, Finland; JOSÉ

LUIS AYUSO-MATEOS, M.D., Dept., of Psychiatry, University of Madrid, Spain; GREG

WILKINSON, M.D. Department of Psychiatry, University of Liverpool, UK, GRAHAM

DUNN, Dept. of Statistics, University of Manchester, UK., CLARE WILKINSON, M.D.,

Department of General Practice, University of Wales College of Medicine, UK; JOSÉ LUIS

VÁZQUEZ-BARQUERO, M.D., University Hospital Marqués de Valdicella, Santander,

Spain..