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Validity of the depressive dimension extracted from principal component analysis of the PANSS in drug-free patients with schizophrenia
Schizophrenia Research 56 (2002) 121±127
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Validity of the depressive dimension extracted from principal component analysis of the PANSS in drug-free patients with schizophrenia Meriem El Yazaji a, Omar Battas a, Mohamed Agoub a, Driss Moussaoui a, Christel Gutknecht b, Jean Dalery b, Thierry d'Amato b,*, Mohamed Saoud b,c b
a Centre Psychiatrique Universitaire Ibn Rochd, rue Tarik Ibn Ziad, Casablanca, Morocco Centre Hospitalier `Le Vinatier', E.A. 3092 (Universite Lyon 1), 95 boulevard Pinel, F-69677 Bron cedex, France c INSERM U534, 16 avenue LeÂpine, F-69676 Bron cedex, France
Received 18 November 2000; accepted 10 April 2001
Abstract Depressive symptoms frequently occur during the course of schizophrenia. This study explored the relationships between the schizophrenia symptomatology and three measures of depression. Eighty-one drug-free inpatients with acute schizophrenia were assessed with the positive and negative syndrome scale (PANSS), the Calgary depression scale for schizophrenia (CDSS), and the Hamilton rating scale for depression (HAM-D). The depressive subscale of PANSS (PANSS-D) was also considered as a third scale for measuring depression. A principal component analysis (PCA) of PANSS items identi®ed ®ve clinical dimensions of schizophrenia called `negative', `positive', `anxio-depressive', `excitement', and `disorganisation and others'. Our anxio-depressive dimension (PANSS-ad) was strictly identical with the PANSS-D. Scores on CDSS and HAM-D were highly inter-correlated and highly correlated with the PANSS-ad. Furthermore, while scores on CDSS were correlated only with this dimension, scores at HAM-D were also positively correlated with the negative dimension and negatively correlated with the excitement dimension. In conclusion, our results suggest that PANSS evaluation itself may be suf®cient to give a correct approximation of the depression in patients with schizophrenia. However, depression scales are of course needed to assess speci®cally depressive symptoms in patients with schizophrenia; hence, the CDSS could be a more speci®c instrument than HAM-D. q 2002 Elsevier Science B.V. All rights reserved. Keywords: Depression; Schizophrenia; PANSS; Depression scales
1. Introduction Schizophrenia has long been described as a clinically heterogeneous entity. The positive±negative distinction has been an interesting strategy to * Corresponding author. Tel.: 133-437915100; fax: 133437915102. E-mail address: [email protected] (T. d'Amato).
delineate this heterogeneity and several instruments were developed to explore this dichotomy. However, its adequacy has been challenged through reports showing the failure of dichotomic models (Liddle, 1987; Arndt et al., 1991) and favouring the multidimensional structure of schizophrenia. Indeed, recent factor analysis studies, using the positive and negative syndrome scale (PANSS; Kay et al., 1987), suggest that a structure with three or more dimensions appears
0920-9964/02/$ - see front matter q 2002 Elsevier Science B.V. All rights reserved. PII: S 0920-996 4(01)00247-X
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M. El Yazaji et al. / Schizophrenia Research 56 (2002) 121±127
to best ®t the assessed psychopathology (Kay and Sevy, 1990; Dollfus et al., 1991; Bell, 1994; Lindenmayer et al., 1995; White et al., 1997; Nakaya et al., 1999; Mass et al., 2000). Among these, the so-called depressive or anxio-depressive dimension was frequently observed. Such evidence is not at variance with clinical observations. Indeed, symptoms of depression are frequent in schizophrenia in all phases of the illness (Zisook et al., 1999) and it has been estimated that 25±80% of patients with schizophrenia exhibit depressive symptoms (Birchwood et al., 1993; Mauri et al., 1995). They contribute to social impairments and are often associated with an increased risk of relapse and suicide (Jones et al., 1994; Ram et al., 1995; Emsly et al., 1999). In patients with schizophrenia, such depressive symptoms are often evaluated throughout psychometric tools such as the Hamilton rating scale for depression (HAM-D; Hamilton, 1960) and the Calgary depression scale for schizophrenia (CDSS; Addington et al., 1990). However, the value of HAM-D has not been substantiated in schizophrenia (Reine et al., 1998), because this scale contains items that correlate strongly with negative or positive symptomatology (Goldman et al., 1992; Addington et al., 1996; Sax et al., 1996; Reine et al., 1998). In contrast, CDSS is a structured interview, speci®cally developed to measure depression in schizophrenia. The construct and predictive validity of this scale is supported by the ®nding that it speci®cally measures depression, rather than positive, negative or antipsychotic induced side effects (Addington et al., 1994; Reine et al., 1998; Bernard et al., 1998). Collins et al. (1996) have looked for such relationships between scores from CDSS, HAM-D and the PANSS depression subscale (PANSS-D), with a signi®cant correlation between these three scales in treated chronic outpatients with schizophrenia. Kontaxakis et al. (2000) examined the association between schizophrenia symptoms and different depression scales: CDSS, HAM-D, PANSS-D, and expanded brief psychiatric rating scale±depression subscale (EBPRS-D) in a group of treated inpatients with acute schizophrenia. They found that only CDSS and EBPRS-D can discriminate between depression and PANSS negative symptoms subscale scores. However, to our knowledge no authors have examined relationships between scores on such depression scales and the several clinical dimensions extracted
from principal component analysis (PCA) of PANSS items. The present report examines the relationships between scores on three scales for measuring depression (HAM-D, CDSS, PANSS-D) and the PANSS extracted dimensions, particularly with a putative `depressive dimension', in a group of drug-free inpatients with acute schizophrenia. 2. Method 2.1. Subjects All patients were recruited and evaluated by a single rater (M.E.) at the `Centre Psychiatrique Universitaire' of Casablanca (Morocco), once the research method was approved by the local ethical committee. All solicited patients consented to participate after the procedure was explained to them. Concerning psychotropic medications, all subjects had to have been either drug-naive or drug-free for more than three months at the time of testing. Exclusion criteria were a current history of alcohol or substance abuse, and any neurological trauma or disease. The sample consisted of 81 acute inpatients with a DSM-IV diagnosis of schizophrenia based on the structured clinical interview for DSM-IV (SCID; First et al., 1995) rated by a trained psychiatrist. Demographic details are reported in Table 1. 2.2. Clinical assessments Schizophrenia symptoms were evaluated with the French version of the PANSS (LeÂpine et al., 1989; LancËon et al., 1999a). Depressive symptoms were evaluated with the French versions of HAM-D (Collet and Cottraux, 1986), of CDSS (Bernard et al., 1998; LancËon et al., 1999b) and PANSS-D. The last mentioned evaluation tool is a subscale of PANSS composed of four items: somatic concern (G1), anxiety (G2), guilt feeling (G3) and depression (G6). 2.3. Statistical analysis As a ®rst step, a PCA was performed using the matrix correlation between the 30 items of PANSS. The number of extracted factors was decided using
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Table 1 Demographic characteristics and psychometric scores in a sample of 81 drug-free inpatients with acute schizophrenia (S.D.: standard deviations, HAM-D: Hamilton rating scale for depression, CDSS: Calgary depression scale for schizophrenia). Patients at ®rst hospitalisation (mean scores ^ S:D:): HAM-D (9:03 ^ 4:43), CDSS (8:00 ^ 5:92); patients with more than one hospitalisation (mean scores ^ S:D:): HAM-D (9:19 ^ 5:19), CDSS (6:53 ^ 5:09)) Variables
Age (years) Duration of illness (years) Educational level (years) PANSS (total score) Negative Positive Psychopathology Depressive (PANSS-D) HAM-D (total score) CDSS (total score)
Mean ^ S:D: Total sample n 81
Males n 71
Females n 10
30.42 ^ 6.83 5.75 ^ 4.65 8.51 ^ 4.58 84.8 ^ 12.27 21.84 ^ 5.79 23.01 ^ 6.38 40.21 ^ 6.82 8.60 ^ 3.01 9.12 ^ 4.86 7.15 ^ 5.46
30.20 ^ 6.65 5.57 ^ 4.63 8.80 ^ 4.54 84.34 ^ 12.73 21.76 ^ 5.97 23.00 ^ 6.63 39.94 ^ 6.79 8.33 ^ 2.58 8.66 ^ 4.42 6.52 ^ 4.63
32.00 ^ 8.19 7.10 ^ 4.84 6.50 ^ 4.57 88.10 ^ 8.10 22.40 ^ 4.60 23.10 ^ 4.48 42.10 ^ 7.06 10.50 ^ 4.90 12.4 ^ 6.65 11.6 ^ 8.59
Kaiser's criteria and the Cattell's screen test before subsequent VARIMAX rotation. As a second step, Pearson correlations were used to examine relationships between scores on HAM-D, CDSS, and PANSS-D and each dimension of PANSS. Analyses were performed using spss software (version 9.0.1 for Windows, 1999). 3. Results In the ®rst step, ®ve dimensions were retained from PANSS, explaining 56.7% of the total variance (Table 2). Given their item composition, we propose calling these dimensions: negative (PANSS-n), positive (PANSS-p), anxio-depressive (PANSS-ad), excitement (PANSS-e), disorganisation and others (PANSS-d). The negative dimension (component 1) explained 19.4% of the total variance and consisted of active social avoidance (G16), passive-apathetic social withdrawal (N4), lack of spontaneity and ¯ow of conversation (N6), emotional withdrawal (N2), preoccupation (G15), blunted affect (N1), poor rapport (N3), disturbance of volition (G13), motor retardation (G7), and poor attention (G11). The positive dimension (component 2) accounted for 9% of the variance and comprised suspiciousness/persecution (P6), delusion (P1), hallucinatory behaviour (P3), grandiosity (P5) and lack of judgment and insight
(G12). The anxio-depressive dimension came through as component 3, accounting for 7.9% of the variance, and comprised guilt feelings (G3), depression (G6), somatic concern (G1), and anxiety (G2). The composition of this dimension is identical to the PANSS-D. The excitement dimension (component 4) explained 7.8% of the variance and consisted of poor impulse control (G14), excitement (P4) and hostility (P7). The ®fth dimension, called disorganisation and others consisted of mannerisms and posturing (G5), stereotyped thinking (N7), conceptual disorganisation (P2), dif®culty in abstract thinking (N5) and unusual thought content (G9) and represented 12.3% of variance. Three items did not appear in any dimension: uncooperativeness (G8), tension (G4) and disorientation (G10). In the second step, we looked for a correlation between scores on the three depression scales and the ®ve dimensions extracted from PANSS (Table 3). There was a high degree of correlation between scores on HAMD and CDSS. There was also a high degree of correlation between these scores and PANSS-ad, being signi®cantly higher for CDSS than for HAM-D (p 0:0014). At the threshold of 5%, the HAM-D score was also positively correlated with PANSS-n and negatively correlated with PANSS-e (Table 3). The severity of symptoms, age, gender, duration of illness and educational level have no effect on the strength of the correlation.
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Table 2 Means, standard deviations, and components of 30 items of PANSS in a sample of 81 drug-free inpatients with acute schizophrenia (S.D.: standard deviation, component loading . 0:4 were represented) PANSS items
Components Mean
S.D.
3.91 3.95
0.99 1.05
0.84 0.82
3.31
1.29
0.80
2.79 3.78 3.35 3.26 2.90 3.56 2.46
1.10 2.56 1.14 1.22 1.17 1.32 1.12
0.78 0.76 0.75 0.70 0.59 0.56 0.40
3.28 4.19 4.09 1.98 4.09
1.40 1.22 1.27 1.29 1.28
Anxio-depressive dimension Guilt feelings (G3) Depression (G6) Somatic concern (G1) Anxiety (G2)
2.05 2.28 1.95 2.32
0.95 1.12 1.13 1.01
Excitement dimension Poor impulse control (G14) Excitement (P4) Hostility (P7)
2.69 2.81 2.37
1.16 1.15 1.09
1.20 1.48 4.14 3.59
0.58 0.92 1.34 1.07
3.25
1.24
Negative dimension Active social avoidance (G16) Passive/apathetic social withdrawal (N4) Lack of spontaneity/¯ow of conversation (N6) Emotional withdrawal (N2) Preoccupation (G15) Blunted affect (N1) Poor rapport (N3) Disturbance of volition (G13) Motor retardation (G7) Poor attention (G11) Positive dimension Suspiciousness/persecution (P6) Delusions (P1) Hallucinatory behaviour (P3) Grandiosity (P5) Lack of judgement and insight (G12)
Disorganisation dimension and others Mannerisms/posturing (G5) Stereotyped thinking (N7) Conceptual disorganisation (P2) Dif®culty in abstract thinking (N5) Unusual thought content (G9) Variance (%)
4. Discussion The aim of this study was to explore the relationships between PANSS-extracted dimensions and scores on three scales for measuring depression (HAM-D, CDSS and PANSS-D), on a sample of drug-free inpatients with acute schizophrenia.
1
2
3
4
5
6
0.81 0.67 0.63 0.44 0.43
0.81 0.74 0.61 0.58 0.85 0.78 0.73 0.88 0.82 0.55 0.54 19.4
9.0
0.74 0.53 0.50
7.9
7.8
6.6
5.7
We initially extracted ®ve dimensions of schizophrenia from PCA of PANSS items. Interestingly, both the PANSS-ad and the PANSS-D were composed of the same four items. In the second step, we found a correlation between PANSS-ad and scores on CDSS and HAM-D. However, some methodological issues have to be
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Table 3 Pearson's coef®cients of correlations between scores on depressive scales and PANSS extracted dimensions in a sample of 81 drug-free inpatients with acute schizophrenia ( * signi®cance at 0.05 level, ** signi®cance at 0.001 level, CDSS: Calgary depression scale for schizophrenia; HAM-D: Hamilton rating scale for depression) PANSS dimension 3 anxiodepressive CDSS HAM-D PANSS dimension 1 negative PANSS dimension 2 positive PANSS dimension 4 excitement PANSS dimension 5 disorganisation and others
0.782 ** 0.586 ** 0.094 0.047 20.131 20.009
CDSS
HAM-D
0.680 ** 0.076 0.029 20.176 20.069
0.266 * 20.056 20.245 * 0.032
considered. Several characteristics of the sample may have in¯uenced depression scores. First, more males than females were included in the study. This sexratio disequilibrium could reduce depression scores given that men are known to exhibit depressive symptoms to a lesser degree than women (Emsly et al., 1999). However, this overrepresentation of males did not prevent the extraction of an anxio-depressive dimension identical to the PANSS-D and signi®cantly correlated with scores at the two other depression scales (CDSS and HAM-D). Secondly, 42% of the sample were hospitalised for the ®rst time. In patients with recent schizophrenia onset, depressive symptoms are particularly frequent (Koreen et al., 1993; Emsly et al., 1999). Our data accords with this observation. Thirdly, antipsychotic treatments are known to either ameliorate or induce depressive symptoms in patients with schizophrenia (Krakowski et al., 1997) and the number of dimensions identi®ed using PANSS may vary in accordance with the phases of the illness (Loas et al., 1997; Nakaya et al., 1999). As a way to avoid the effects of such issues, we have chosen to study a sample of acute drug-free inpatients. Lastly, the depression ratings were not blind to PANSS scores and some bias in ®nding a correlation between depression scores could not be excluded. These issues having been reviewed, our results con®rm other reports on the clinical dimensions of schizophrenia. Indeed, our ®ve-dimension solution, which includes an anxio-depressive dimension, accords with previous studies based on PANSS (Kay and Sevy, 1990; Lindenmayer et al., 1995; Nakaya et
al., 1999; Mass et al., 2000). This PANSS-ad dimension contains the items depression (G6) and guilt feeling (G3), which are core symptoms in depression. In addition, it contains other frequent symptoms in depressive states, such as anxiety (G2) and somatic concern (G1). This last symptom was not present in the depressive factor of Lindenmayer et al. (1995) but was part of the depressive component of Kay and Sevy (1990). Concerning the relationships between scales for measuring depression, our results accord with previous data. We observed a strong correlation between scores for CDSS and HAM-D, as reported by others (Collins et al., 1996; Kontaxakis et al., 2000). Furthermore, in a sample of treated chronic outpatients with schizophrenia, Collins et al. (1996) also reported strong relationships between scores on these two depression scales and the PANSS-D, equivalent to our PANSS anxio-depressive dimension. With the same tools, Kontaxakis et al. (2000) reported the same correlations in a sample of treated acute inpatients with schizophrenia, but to a lesser degree. Globally, relationships between scores on depression scales and PANSS-D are thus present whatever the stage of the illness (acute or chronic) and whether the subjects are treated or not. Several studies have shown that the CDSS is more speci®c than HAM-D in patients with schizophrenia (Addington et al., 1994; Reine et al., 1998; Bernard et al., 1998). Accordingly, we found a stronger correlation between CDSS and PANSS-ad scores than between HAM-D and PANSS-ad scores, with a
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signi®cant difference (p 0:0014). In our study, CDSS scores are only correlated with PANSS-ad, while HAMD scores are positively correlated with PANSS-n and negatively correlated with PANSS-e. Globally, this might con®rm the greater speci®city of CDSS over HAM-D in assessing actual depressive symptoms in patients with schizophrenia. In conclusion, our results suggest that PANSS evaluation alone may be suf®cient to give a correct approximation of depression in patients with schizophrenia. However, several important symptoms of depression, including suicidal ideation, do not ®gure among PANSS items. Therefore, depression scales remains needed to speci®cally evaluate the depressive symptomatology of schizophrenia. In this context, CDSS appears as a more speci®c instrument than HAM-D. Acknowledgements Grant from Centre Hospitalier Le Vinatier and Conseil Scienti®que de la Recherche du Vinatier (Lyon, France). Acknowledgments to the Medical School of Casablanca and Centre Hospitalier Universitaire Ibn Rochd (Casablanca, Morroco). Acknowledgments to Dr P. Bain for English corrections. References Addington, D., Addington, J., Schissel, B., 1990. A depression rating scale for schizophrenics. Schizophr. Res. 3, 247±251. Addington, D., Addington, J., Maticka-Tyndale, E., 1994. Speci®city of the Calgary depression scale for schizophrenics. Schizophr. Res. 11, 239±244. Addington, D., Addington, J., Atkinson, M., 1996. A psychometric comparison of the Calgary depression scale for schizophrenia and the Hamilton depression rating scale. Schizophr. Res. 19, 205±212. Arndt, S., Alliger, R.J., Andreasen, N.C., 1991. The distinction of positive and negative symptoms: The failure of a two-dimensional model. Br. J. Psychiatry 158, 317±322. Bell, M.D., Lysaker, P.h., Beam-Goulet, J.l., Milstein, R.M., Lindenmayer, J.P., 1994. Five component model of schizophrenia: assessing the factorial invariance of the positive and negative syndrome scale. Psychiatry Res. 52, 295±303. Bernard, D., LancËon, C., Auquier, P., Reine, G., Addington, D., 1998. Calgary depression scale for schizophrenia: a study of the validity of a French language version in a population of schizophrenic patients. Acta. Psychiatr. Scand. 97, 36±41.
Birchwood, M., Mason, R., Macmillan, F., Healy, J., 1993. Depression, demoralization and control over psychotic illness: a comparison of depressed and no depressed patients with a chronic psychosis. Psychol. Med. 23, 387±395. Collet, L., Cottraux, J., 1986. Inventaire abreÂge de la deÂpression de Beck (13 items). Etude de la validite concurrente avec les eÂchelles de Hamilton et de ralentissement deÂpressif de Widlocher. EnceÂphale 12, 77±79. Collins, A.A., Remington, G., Coulter, K., Birkett, K., 1996. Depression in schizophrenia: a comparison of three measures. Schizophr. Res. 20, 205±209. Dollfus, S., Petit, M., Lesieur, P., Menard, J.F., 1991. Principal component analysis of PANSS and SANS±SAPS global ratings in schizophrenic patients. Eur. Psychiatry 6, 251±259. Emsly, R.A., Oosthuizen, P.P., Joubert, A.F., Roberts, M.C., Stein, D.J., 1999. Depressive and anxiety symptoms inpatients with schizophrenia and schizophreniform disorder. J. Clin. Psychiatry 60, 747±751. First, M.G., Spitzer, R.L., Gibbon, M., Williams, J.B., 1995. Structured clinical interview for DSM-IV, Patients edition (SCID-P) New York. Biometrics Research Department, New York State Psychiatric Institute, New York. Goldman, R.S., Tandon, R., Liberzon, I., Greden, J.F., 1992. Measurement of depression and negative symptoms in schizophrenia. Psychopathology 25, 49±56. Hamilton, M., 1960. A rating scale for depression. J. Neurol. Neurosurg. Psychiatry 23, 5662. Jones, J.S., Stein, D.J., Stanley, B., Guido, J.B., Winchel, R., Stanley, M., 1994. Negative and depressive symptoms in suicidal schizophrenics. Acta Psychiatr. Scand. 89, 81±87. Kay, S.R., Sevy, S., 1990. Pyramidical model of schizophrenia. Schizophr. Bull. 16, 537±545. Kay, S.R., Fisbein, A., Opler, A., 1987. The positive and negative syndrome scale (PANSS) for schizophrenia. Schizophr. Bull. 13, 261±276. Kontaxakis, V.P., Havaki-kontaxaki, B.J., Stamouli, S.S., Margariti, M.M., Collias, C.T., Christodoulou, G.N., 2000. Comparison of four scales measuring depression in schizophrenic inpatients. Eur. Psychiatry 15, 274±277. Koreen, A.R., Siris, S.G., Chakos, M., Alvir, J., Mayerhoff, D., Lieberman, J., 1993. Depression in ®rst episode schizophrenia. Am. J. Psychiatry 150, 1643±1648. Krakowski, M., Czobor, P., Volavka, J., 1997. Effect of neuroleptic treatment on depressive symptoms in acute schizophrenic episodes. Psychiatry Res. 71, 19±26. LancËon, C., Aghababian, V., Llorca, P.M., Bernard, D., Auquier, P., 1999a. An exploration of the psychometric properties of the French version of the positive and negative syndrome scale. Can. J. Psychiatry 44, 893±900. LancËon, C., Auquier, P., Reine, G., Toumi, M., Addington, D., 1999b. Evaluation of depression in schizophrenia. Psychometric properties of a French version of the Calgary depression scale. Psychiatry Res. 89, 123±132. LeÂpine, J.P., Piron, J.J., Chapotot, E., 1989. Factor analysis of the PANSS in schizophrenic patients. In: Stefanis, C.N., Soldatos, C.R., Rabavilas, A.D. (Eds.), Psychiatry Today: Accomplishments and Promises. CongreÂs mondial de
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Validity of the depressive dimension extracted from principal component analysis of the PANSS in drug-free patients with schizophrenia Meriem El Yazaji a, Omar Battas a, Mohamed Agoub a, Driss Moussaoui a, Christel Gutknecht b, Jean Dalery b, Thierry d'Amato b,*, Mohamed Saoud b,c b
a Centre Psychiatrique Universitaire Ibn Rochd, rue Tarik Ibn Ziad, Casablanca, Morocco Centre Hospitalier `Le Vinatier', E.A. 3092 (Universite Lyon 1), 95 boulevard Pinel, F-69677 Bron cedex, France c INSERM U534, 16 avenue LeÂpine, F-69676 Bron cedex, France
Received 18 November 2000; accepted 10 April 2001
Abstract Depressive symptoms frequently occur during the course of schizophrenia. This study explored the relationships between the schizophrenia symptomatology and three measures of depression. Eighty-one drug-free inpatients with acute schizophrenia were assessed with the positive and negative syndrome scale (PANSS), the Calgary depression scale for schizophrenia (CDSS), and the Hamilton rating scale for depression (HAM-D). The depressive subscale of PANSS (PANSS-D) was also considered as a third scale for measuring depression. A principal component analysis (PCA) of PANSS items identi®ed ®ve clinical dimensions of schizophrenia called `negative', `positive', `anxio-depressive', `excitement', and `disorganisation and others'. Our anxio-depressive dimension (PANSS-ad) was strictly identical with the PANSS-D. Scores on CDSS and HAM-D were highly inter-correlated and highly correlated with the PANSS-ad. Furthermore, while scores on CDSS were correlated only with this dimension, scores at HAM-D were also positively correlated with the negative dimension and negatively correlated with the excitement dimension. In conclusion, our results suggest that PANSS evaluation itself may be suf®cient to give a correct approximation of the depression in patients with schizophrenia. However, depression scales are of course needed to assess speci®cally depressive symptoms in patients with schizophrenia; hence, the CDSS could be a more speci®c instrument than HAM-D. q 2002 Elsevier Science B.V. All rights reserved. Keywords: Depression; Schizophrenia; PANSS; Depression scales
1. Introduction Schizophrenia has long been described as a clinically heterogeneous entity. The positive±negative distinction has been an interesting strategy to * Corresponding author. Tel.: 133-437915100; fax: 133437915102. E-mail address: [email protected] (T. d'Amato).
delineate this heterogeneity and several instruments were developed to explore this dichotomy. However, its adequacy has been challenged through reports showing the failure of dichotomic models (Liddle, 1987; Arndt et al., 1991) and favouring the multidimensional structure of schizophrenia. Indeed, recent factor analysis studies, using the positive and negative syndrome scale (PANSS; Kay et al., 1987), suggest that a structure with three or more dimensions appears
0920-9964/02/$ - see front matter q 2002 Elsevier Science B.V. All rights reserved. PII: S 0920-996 4(01)00247-X
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to best ®t the assessed psychopathology (Kay and Sevy, 1990; Dollfus et al., 1991; Bell, 1994; Lindenmayer et al., 1995; White et al., 1997; Nakaya et al., 1999; Mass et al., 2000). Among these, the so-called depressive or anxio-depressive dimension was frequently observed. Such evidence is not at variance with clinical observations. Indeed, symptoms of depression are frequent in schizophrenia in all phases of the illness (Zisook et al., 1999) and it has been estimated that 25±80% of patients with schizophrenia exhibit depressive symptoms (Birchwood et al., 1993; Mauri et al., 1995). They contribute to social impairments and are often associated with an increased risk of relapse and suicide (Jones et al., 1994; Ram et al., 1995; Emsly et al., 1999). In patients with schizophrenia, such depressive symptoms are often evaluated throughout psychometric tools such as the Hamilton rating scale for depression (HAM-D; Hamilton, 1960) and the Calgary depression scale for schizophrenia (CDSS; Addington et al., 1990). However, the value of HAM-D has not been substantiated in schizophrenia (Reine et al., 1998), because this scale contains items that correlate strongly with negative or positive symptomatology (Goldman et al., 1992; Addington et al., 1996; Sax et al., 1996; Reine et al., 1998). In contrast, CDSS is a structured interview, speci®cally developed to measure depression in schizophrenia. The construct and predictive validity of this scale is supported by the ®nding that it speci®cally measures depression, rather than positive, negative or antipsychotic induced side effects (Addington et al., 1994; Reine et al., 1998; Bernard et al., 1998). Collins et al. (1996) have looked for such relationships between scores from CDSS, HAM-D and the PANSS depression subscale (PANSS-D), with a signi®cant correlation between these three scales in treated chronic outpatients with schizophrenia. Kontaxakis et al. (2000) examined the association between schizophrenia symptoms and different depression scales: CDSS, HAM-D, PANSS-D, and expanded brief psychiatric rating scale±depression subscale (EBPRS-D) in a group of treated inpatients with acute schizophrenia. They found that only CDSS and EBPRS-D can discriminate between depression and PANSS negative symptoms subscale scores. However, to our knowledge no authors have examined relationships between scores on such depression scales and the several clinical dimensions extracted
from principal component analysis (PCA) of PANSS items. The present report examines the relationships between scores on three scales for measuring depression (HAM-D, CDSS, PANSS-D) and the PANSS extracted dimensions, particularly with a putative `depressive dimension', in a group of drug-free inpatients with acute schizophrenia. 2. Method 2.1. Subjects All patients were recruited and evaluated by a single rater (M.E.) at the `Centre Psychiatrique Universitaire' of Casablanca (Morocco), once the research method was approved by the local ethical committee. All solicited patients consented to participate after the procedure was explained to them. Concerning psychotropic medications, all subjects had to have been either drug-naive or drug-free for more than three months at the time of testing. Exclusion criteria were a current history of alcohol or substance abuse, and any neurological trauma or disease. The sample consisted of 81 acute inpatients with a DSM-IV diagnosis of schizophrenia based on the structured clinical interview for DSM-IV (SCID; First et al., 1995) rated by a trained psychiatrist. Demographic details are reported in Table 1. 2.2. Clinical assessments Schizophrenia symptoms were evaluated with the French version of the PANSS (LeÂpine et al., 1989; LancËon et al., 1999a). Depressive symptoms were evaluated with the French versions of HAM-D (Collet and Cottraux, 1986), of CDSS (Bernard et al., 1998; LancËon et al., 1999b) and PANSS-D. The last mentioned evaluation tool is a subscale of PANSS composed of four items: somatic concern (G1), anxiety (G2), guilt feeling (G3) and depression (G6). 2.3. Statistical analysis As a ®rst step, a PCA was performed using the matrix correlation between the 30 items of PANSS. The number of extracted factors was decided using
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Table 1 Demographic characteristics and psychometric scores in a sample of 81 drug-free inpatients with acute schizophrenia (S.D.: standard deviations, HAM-D: Hamilton rating scale for depression, CDSS: Calgary depression scale for schizophrenia). Patients at ®rst hospitalisation (mean scores ^ S:D:): HAM-D (9:03 ^ 4:43), CDSS (8:00 ^ 5:92); patients with more than one hospitalisation (mean scores ^ S:D:): HAM-D (9:19 ^ 5:19), CDSS (6:53 ^ 5:09)) Variables
Age (years) Duration of illness (years) Educational level (years) PANSS (total score) Negative Positive Psychopathology Depressive (PANSS-D) HAM-D (total score) CDSS (total score)
Mean ^ S:D: Total sample n 81
Males n 71
Females n 10
30.42 ^ 6.83 5.75 ^ 4.65 8.51 ^ 4.58 84.8 ^ 12.27 21.84 ^ 5.79 23.01 ^ 6.38 40.21 ^ 6.82 8.60 ^ 3.01 9.12 ^ 4.86 7.15 ^ 5.46
30.20 ^ 6.65 5.57 ^ 4.63 8.80 ^ 4.54 84.34 ^ 12.73 21.76 ^ 5.97 23.00 ^ 6.63 39.94 ^ 6.79 8.33 ^ 2.58 8.66 ^ 4.42 6.52 ^ 4.63
32.00 ^ 8.19 7.10 ^ 4.84 6.50 ^ 4.57 88.10 ^ 8.10 22.40 ^ 4.60 23.10 ^ 4.48 42.10 ^ 7.06 10.50 ^ 4.90 12.4 ^ 6.65 11.6 ^ 8.59
Kaiser's criteria and the Cattell's screen test before subsequent VARIMAX rotation. As a second step, Pearson correlations were used to examine relationships between scores on HAM-D, CDSS, and PANSS-D and each dimension of PANSS. Analyses were performed using spss software (version 9.0.1 for Windows, 1999). 3. Results In the ®rst step, ®ve dimensions were retained from PANSS, explaining 56.7% of the total variance (Table 2). Given their item composition, we propose calling these dimensions: negative (PANSS-n), positive (PANSS-p), anxio-depressive (PANSS-ad), excitement (PANSS-e), disorganisation and others (PANSS-d). The negative dimension (component 1) explained 19.4% of the total variance and consisted of active social avoidance (G16), passive-apathetic social withdrawal (N4), lack of spontaneity and ¯ow of conversation (N6), emotional withdrawal (N2), preoccupation (G15), blunted affect (N1), poor rapport (N3), disturbance of volition (G13), motor retardation (G7), and poor attention (G11). The positive dimension (component 2) accounted for 9% of the variance and comprised suspiciousness/persecution (P6), delusion (P1), hallucinatory behaviour (P3), grandiosity (P5) and lack of judgment and insight
(G12). The anxio-depressive dimension came through as component 3, accounting for 7.9% of the variance, and comprised guilt feelings (G3), depression (G6), somatic concern (G1), and anxiety (G2). The composition of this dimension is identical to the PANSS-D. The excitement dimension (component 4) explained 7.8% of the variance and consisted of poor impulse control (G14), excitement (P4) and hostility (P7). The ®fth dimension, called disorganisation and others consisted of mannerisms and posturing (G5), stereotyped thinking (N7), conceptual disorganisation (P2), dif®culty in abstract thinking (N5) and unusual thought content (G9) and represented 12.3% of variance. Three items did not appear in any dimension: uncooperativeness (G8), tension (G4) and disorientation (G10). In the second step, we looked for a correlation between scores on the three depression scales and the ®ve dimensions extracted from PANSS (Table 3). There was a high degree of correlation between scores on HAMD and CDSS. There was also a high degree of correlation between these scores and PANSS-ad, being signi®cantly higher for CDSS than for HAM-D (p 0:0014). At the threshold of 5%, the HAM-D score was also positively correlated with PANSS-n and negatively correlated with PANSS-e (Table 3). The severity of symptoms, age, gender, duration of illness and educational level have no effect on the strength of the correlation.
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Table 2 Means, standard deviations, and components of 30 items of PANSS in a sample of 81 drug-free inpatients with acute schizophrenia (S.D.: standard deviation, component loading . 0:4 were represented) PANSS items
Components Mean
S.D.
3.91 3.95
0.99 1.05
0.84 0.82
3.31
1.29
0.80
2.79 3.78 3.35 3.26 2.90 3.56 2.46
1.10 2.56 1.14 1.22 1.17 1.32 1.12
0.78 0.76 0.75 0.70 0.59 0.56 0.40
3.28 4.19 4.09 1.98 4.09
1.40 1.22 1.27 1.29 1.28
Anxio-depressive dimension Guilt feelings (G3) Depression (G6) Somatic concern (G1) Anxiety (G2)
2.05 2.28 1.95 2.32
0.95 1.12 1.13 1.01
Excitement dimension Poor impulse control (G14) Excitement (P4) Hostility (P7)
2.69 2.81 2.37
1.16 1.15 1.09
1.20 1.48 4.14 3.59
0.58 0.92 1.34 1.07
3.25
1.24
Negative dimension Active social avoidance (G16) Passive/apathetic social withdrawal (N4) Lack of spontaneity/¯ow of conversation (N6) Emotional withdrawal (N2) Preoccupation (G15) Blunted affect (N1) Poor rapport (N3) Disturbance of volition (G13) Motor retardation (G7) Poor attention (G11) Positive dimension Suspiciousness/persecution (P6) Delusions (P1) Hallucinatory behaviour (P3) Grandiosity (P5) Lack of judgement and insight (G12)
Disorganisation dimension and others Mannerisms/posturing (G5) Stereotyped thinking (N7) Conceptual disorganisation (P2) Dif®culty in abstract thinking (N5) Unusual thought content (G9) Variance (%)
4. Discussion The aim of this study was to explore the relationships between PANSS-extracted dimensions and scores on three scales for measuring depression (HAM-D, CDSS and PANSS-D), on a sample of drug-free inpatients with acute schizophrenia.
1
2
3
4
5
6
0.81 0.67 0.63 0.44 0.43
0.81 0.74 0.61 0.58 0.85 0.78 0.73 0.88 0.82 0.55 0.54 19.4
9.0
0.74 0.53 0.50
7.9
7.8
6.6
5.7
We initially extracted ®ve dimensions of schizophrenia from PCA of PANSS items. Interestingly, both the PANSS-ad and the PANSS-D were composed of the same four items. In the second step, we found a correlation between PANSS-ad and scores on CDSS and HAM-D. However, some methodological issues have to be
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Table 3 Pearson's coef®cients of correlations between scores on depressive scales and PANSS extracted dimensions in a sample of 81 drug-free inpatients with acute schizophrenia ( * signi®cance at 0.05 level, ** signi®cance at 0.001 level, CDSS: Calgary depression scale for schizophrenia; HAM-D: Hamilton rating scale for depression) PANSS dimension 3 anxiodepressive CDSS HAM-D PANSS dimension 1 negative PANSS dimension 2 positive PANSS dimension 4 excitement PANSS dimension 5 disorganisation and others
0.782 ** 0.586 ** 0.094 0.047 20.131 20.009
CDSS
HAM-D
0.680 ** 0.076 0.029 20.176 20.069
0.266 * 20.056 20.245 * 0.032
considered. Several characteristics of the sample may have in¯uenced depression scores. First, more males than females were included in the study. This sexratio disequilibrium could reduce depression scores given that men are known to exhibit depressive symptoms to a lesser degree than women (Emsly et al., 1999). However, this overrepresentation of males did not prevent the extraction of an anxio-depressive dimension identical to the PANSS-D and signi®cantly correlated with scores at the two other depression scales (CDSS and HAM-D). Secondly, 42% of the sample were hospitalised for the ®rst time. In patients with recent schizophrenia onset, depressive symptoms are particularly frequent (Koreen et al., 1993; Emsly et al., 1999). Our data accords with this observation. Thirdly, antipsychotic treatments are known to either ameliorate or induce depressive symptoms in patients with schizophrenia (Krakowski et al., 1997) and the number of dimensions identi®ed using PANSS may vary in accordance with the phases of the illness (Loas et al., 1997; Nakaya et al., 1999). As a way to avoid the effects of such issues, we have chosen to study a sample of acute drug-free inpatients. Lastly, the depression ratings were not blind to PANSS scores and some bias in ®nding a correlation between depression scores could not be excluded. These issues having been reviewed, our results con®rm other reports on the clinical dimensions of schizophrenia. Indeed, our ®ve-dimension solution, which includes an anxio-depressive dimension, accords with previous studies based on PANSS (Kay and Sevy, 1990; Lindenmayer et al., 1995; Nakaya et
al., 1999; Mass et al., 2000). This PANSS-ad dimension contains the items depression (G6) and guilt feeling (G3), which are core symptoms in depression. In addition, it contains other frequent symptoms in depressive states, such as anxiety (G2) and somatic concern (G1). This last symptom was not present in the depressive factor of Lindenmayer et al. (1995) but was part of the depressive component of Kay and Sevy (1990). Concerning the relationships between scales for measuring depression, our results accord with previous data. We observed a strong correlation between scores for CDSS and HAM-D, as reported by others (Collins et al., 1996; Kontaxakis et al., 2000). Furthermore, in a sample of treated chronic outpatients with schizophrenia, Collins et al. (1996) also reported strong relationships between scores on these two depression scales and the PANSS-D, equivalent to our PANSS anxio-depressive dimension. With the same tools, Kontaxakis et al. (2000) reported the same correlations in a sample of treated acute inpatients with schizophrenia, but to a lesser degree. Globally, relationships between scores on depression scales and PANSS-D are thus present whatever the stage of the illness (acute or chronic) and whether the subjects are treated or not. Several studies have shown that the CDSS is more speci®c than HAM-D in patients with schizophrenia (Addington et al., 1994; Reine et al., 1998; Bernard et al., 1998). Accordingly, we found a stronger correlation between CDSS and PANSS-ad scores than between HAM-D and PANSS-ad scores, with a
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signi®cant difference (p 0:0014). In our study, CDSS scores are only correlated with PANSS-ad, while HAMD scores are positively correlated with PANSS-n and negatively correlated with PANSS-e. Globally, this might con®rm the greater speci®city of CDSS over HAM-D in assessing actual depressive symptoms in patients with schizophrenia. In conclusion, our results suggest that PANSS evaluation alone may be suf®cient to give a correct approximation of depression in patients with schizophrenia. However, several important symptoms of depression, including suicidal ideation, do not ®gure among PANSS items. Therefore, depression scales remains needed to speci®cally evaluate the depressive symptomatology of schizophrenia. In this context, CDSS appears as a more speci®c instrument than HAM-D. Acknowledgements Grant from Centre Hospitalier Le Vinatier and Conseil Scienti®que de la Recherche du Vinatier (Lyon, France). Acknowledgments to the Medical School of Casablanca and Centre Hospitalier Universitaire Ibn Rochd (Casablanca, Morroco). Acknowledgments to Dr P. Bain for English corrections. References Addington, D., Addington, J., Schissel, B., 1990. A depression rating scale for schizophrenics. Schizophr. Res. 3, 247±251. Addington, D., Addington, J., Maticka-Tyndale, E., 1994. Speci®city of the Calgary depression scale for schizophrenics. Schizophr. Res. 11, 239±244. Addington, D., Addington, J., Atkinson, M., 1996. A psychometric comparison of the Calgary depression scale for schizophrenia and the Hamilton depression rating scale. Schizophr. Res. 19, 205±212. Arndt, S., Alliger, R.J., Andreasen, N.C., 1991. The distinction of positive and negative symptoms: The failure of a two-dimensional model. Br. J. Psychiatry 158, 317±322. Bell, M.D., Lysaker, P.h., Beam-Goulet, J.l., Milstein, R.M., Lindenmayer, J.P., 1994. Five component model of schizophrenia: assessing the factorial invariance of the positive and negative syndrome scale. Psychiatry Res. 52, 295±303. Bernard, D., LancËon, C., Auquier, P., Reine, G., Addington, D., 1998. Calgary depression scale for schizophrenia: a study of the validity of a French language version in a population of schizophrenic patients. Acta. Psychiatr. Scand. 97, 36±41.
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