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Clinical dimensions of auditory hallucinations in schizophrenic disorders
Comprehensive Psychiatry 48 (2007) 337 – 342 www.elsevier.com/locate/comppsych
Clinical dimensions of auditory hallucinations in schizophrenic disorders Panagiotis Oulisa,4, Rossetos Gournellisb, George Konstantakopoulosa, Thomas Matsoukasa, Panagiota G. Michalopouloub, Constantin Soldatosa, Lefteris Lykourasb b
a Department of Psychiatry, University of Athens, Eginition Hospital, 11528 Athens, Greece Second Department of Psychiatry, University of Athens, Attikon Hospital, 12462 Athens, Greece
Abstract Background: Auditory hallucinations occupy, along with delusional beliefs, the center stage of active or bpositiveQ psychotic clinical psychopathology. During the last decade, several sets of auditory hallucinations’ clinical features were subjected to multivariate statistical analyses to disclose major dimensions of psychotic patients’ overall hallucinatory experience and behavior. However, these studies failed, to a large extent, to provide satisfactory external validations of the thereby extracted factors. Methods: We investigated the major clinical dimensions of verbal auditory hallucinations in a sample of 100 inpatients with schizophrenic disorders. Patients (61 men and 39 women) were examined before the initiation of antipsychotic treatment and their assessment included 18 major clinical features of auditory hallucinations. Brief Psychiatric Rating Scale, Hamilton Depression Rating Scale, Global Assessment Scale, and Mini-Mental State Examination were used as external validators. Results: Principal component analysis resulted in the extraction of 5 factors interpreted as the dimensions of severity of auditory hallucinations, emotional and behavioral impact, rate of their intrusion in self-consciousness, delusional elaboration, and similarity to ordinary auditory perception, respectively. The second and third factors extracted in our study correlated with short duration of illness, whereas the first, fourth, and fifth ones correlated with chronicity. Our second factor correlated with clinical severity of patients’ current mental state, the fifth factor with severity of their cognitive impairment, and the first and fourth ones with lower clinical depression despite patients’ chronicity. Conclusion: The findings of our study contribute to the further elucidation of the major clinical dimensions of auditory hallucinations and the testing of their external validity. D 2007 Elsevier Inc. All rights reserved.
1. Introduction Auditory hallucinations occupy, along with delusional beliefs, the center stage of active or bpositiveQ psychotic clinical psychopathology and are, justifiably, incorporated into the diagnostic criteria of psychotic disorders, especially the schizophrenic ones. Their clinical complexity has been acknowledged long ago, at least since Bleuler’s [1] classic monograph on bthe group of schizophrenias,Q wherein various clinical dimensions of hallucinations were explicitly thematized such as intensity—loudness, clarity, outward projection—and reality value—objectivity for the patient. During the last 35 years, several clinical studies focused on various sets of auditory hallucinations’ features and found them to vary independently from 4 Corresponding author. Tel.: +30 2107289408; fax: +30 2107242020. E-mail address: [email protected] (P. Oulis). 0010-440X/$ – see front matter D 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.comppsych.2007.03.006
one another [2-8]. Moreover, during the last decade, several sets of auditory hallucinations’ clinical features were subjected to multivariate statistical analyses to disclose major dimensions of psychotic patients’ overall hallucinatory experience and behavior [9-11]. However, these studies did not provide satisfactory external validations of the extracted factors. For example, in the Haddock et al [9] study, only 1 of 3 factors exhibited external validity, whereas both factors in the study of Singh et al [10] correlated with patients’ Brief Psychiatric Rating Scale (BPRS) score. This fact renders their results—otherwise quite attractive because of their simplicity—rather arbitrary. The aim of the present study is to disclose clinically adequate and prognostically relevant dimensions of auditory hallucinations, taking care to test our solution for validity against a battery of external validators, such as demographic, anamnestic, and concurrent clinical ones.
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P. Oulis et al. / Comprehensive Psychiatry 48 (2007) 337 – 342
2. Materials and methods From January 2005 to March 2006, 100 (61 men and 39 women) consecutive inpatients with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) [12] schizophrenic disorders and active auditory hallucinations on their admission at Eginition Hospital were included in the study. Active auditory hallucinations was defined as the experience of auditory hallucinations on admission to the hospital ward. All patients participating in the study gave written consent to this effect. The only exclusion criteria were patients’ unwillingness to participate in the study or their inability to this effect because of severe agitation or marked cognitive impairment. Patients’ mean age was 34.83 years (SD, 12.42 years) and their years of formal education were 11.20 (SD, 3.36). The mean duration of their illness was 8.98 years (SD, 7.68 years), with a mean number of psychiatric hospitalizations of 2.47 (SD, 2.12). With respect to clinical subtype, 59 were of the paranoid type, 37 of the undifferentiated type, and 4 of the disorganized types. Patients were examined within the first 3 days after their admission, before the initiation of any specifically antipsychotic treatment. At the time of their assessment, patients were receiving only minimal doses of benzodiazepines. Their examination by the first 3 authors (P.O., R.G., and G.K.) included the conduction of a semistructured interview, appropriate to the rating of 18 clinical characteristics of their auditory hallucinations by means of 3-point item scales (see Appendix A). Items selected for study were drawn from the relevant international literature [3-6,13-16]. Concomitantly, patients were also rated on a battery of wellknown clinical scales, including the BPRS [17], the Hamilton Depression Rating Scale (HDRS) [18], the Global Assessment Scale (GAS) [19], and, finally, the Mini-Mental State Examination (MMSE) [20]. Patients’ mean scores on these scales were as follows: BPRS, 58.93 (SD, 10.29); HDRS, 14.73 (SD, 6.68); GAS, 28.54 (SD, 5.96); and MMSE, 24.84 (SD, 3.38). SPSS software (SPSS, Chicago, IL) was used for the statistical analyses of data [21]. Patients’ scores on the item scales were subjected to factor analysis (principal components analysis), initially without rotation and thereafter with varimax rotation. Rotation did not change factors’ internal item composition. For the investigation of the external validity of the factorial solution obtained, Spearman q correlation coefficient values were computed between patients’ factor scores and their demographic and anamnestic data, their total scores on the above-mentioned 4 clinical scales, patients’ length of hospital stay, dosage of antipsychotic medications received during their index hospitalization, and modalities of disposition upon discharge from hospital. The sole exception was the dichotomous variable of sex for which 1-way nonparametric analysis of variance (Kruskal-Wallis) was performed. Interrater reliability of the auditory hallucinations item scales was tested in a subsample of 6 patients by means of
the weighted j statistic [22]. Finally, the extracted factors’ internal consistency was tested by means of Cronbach coefficient a [23].
3. Results The interrater reliability of the item scales was found quite satisfactory because their weighted j statistic values ranged from 0.65 (items of voices’ affective congruence and independence from volition) to 1.00 (for the items of lack of insight and objectivity). DSM-IV diagnostic reliability as well as BPRS, HDRS, and MMSE interrater reliability had been preliminary tested in a sample of 20 patients with schizophrenia with quite satisfactory reliability coefficient values ranging from 0.80 to 1.00. Principal components analysis resulted in the extraction of 8 factors with eigenvalues greater than unity, jointly accounting for 68.8% of the total variance. However, upon applying the scree plot test of eigenvalues we opted for a 5-factor solution, accounting for 52.4% of the total variance. The internal consistency of the 5 factors was also satisfactory, ranging from 0.73 to 0.86. Table 1 displays our main results. The first factor, interpreted as severity of auditory hallucinations, subsumed the items of hallucinations’ duration in each occurrence and the length of hallucinated utterances and was positively correlated to duration of illness and negatively to HDRS score. The second factor, interpreted as emotional and behavioral impact, comprised the items of hallucinatory behavior, affective congruence with hallucinatory content, emotional impact of hallucinatory occurrences, loudness of bvoices,Q patients’ expectation that bystanders also can hear their bvoicesQ as well as near-total independence of hallucinatory occurrences from patients’ volition. This factor was negatively correlated to duration of illness and positively to both BPRS and HDRS scores. Furthermore, the third factor, interpreted as rate of intrusion in self-consciousness, combined the items of frequency of hallucinatory occurrences and of voices commenting on patients’ current thoughts or actions, and was negatively correlated to age, duration of illness, and number of hospitalizations. Moreover, the fourth factor, interpreted as delusional elaboration, subsumed the items of lack of insight and unshakable belief in the actual existence of hallucinations’ emission source, being positively correlated to age and duration of illness as well as negatively correlated to number of hospitalizations and HDRS scores, respectively. Finally, the fifth factor, interpreted as similarity to normal auditory perception, included the items of homogeneity of hallucinations with ordinary auditory perception, patients’ ability to spatially localize their source, clarity of their content, predominance of external over internal hallucinations, predominance of third (over second) person hallucinations as well as absence of nonverbal hallucinations. This factor was negatively correlated to both GAS and MMSE scores
Table 1 Principal components analysis and correlations between factors and external validators Principal components analysis Factor I: severity of auditory hallucinations
Factor III: rate of intrusion in self-consciousness
Factor IV: delusional elaboration
Factor V: similarity to normal auditory perception
0.91
Hallucinatory behavior
0.85
Frequency
0.82
Lack of insight
0.81
Homogeneity
0.82
0.87
Affective congruence
0.82
Commenting voices
0.76
Belief in objectivity of hallucinatory emission source
0.55
Localization of emission source
0.78
Emotional impact Independence from volition Expectation of intersubjectivity
0.80 0.78
0.72 0.68
Loudness
0.45
Clarity of content Predominance of external vs internal hallucinations Predominance of third- vs second-person hallucinations Nonverbal auditory hallucinations
Only loadings N |0.40| are displayed Variance (%) 13.3
0.65
11.2
10.1
9.8
0.46
0.70
8.2
Correlations (r) between factors and external validators Duration of illness HDRS
0.41444 0.39444
Duration of illness BPRS HDRS
0.31444 0.42444 0.2944
Age Duration of illness No. of hospitalizations
0.30444 0.2944 0.40444
Age No. of hospitalizations HDRS
0.254 0.2844 0.38444
Age Duration of illness GAS MMSE
0.264 0.254 0.31444 0.42444
P. Oulis et al. / Comprehensive Psychiatry 48 (2007) 337 – 342
Duration of each hallucinatory occurrence Length of hallucinatory sentences
Factor II: emotional and behavioral impact
4 P b .05. 44 P b .01. 444 P b .00.
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P. Oulis et al. / Comprehensive Psychiatry 48 (2007) 337 – 342
and positively to age and duration of illness. No significant differences were found with respect to patients’ sex or clinical subtype of schizophrenic disorders. Likewise, no significant correlations were found with respect to total doses of antipsychotic medications received during index hospitalization, length of index hospitalization, and modalities of patients’ disposition upon discharge from hospital. 4. Discussion The aim of the present study was to disclose major clinical dimensions of auditory hallucinations in a sample of 100 schizophrenic inpatients and to test for their external validity. The 5 dimensions of auditory hallucinations disclosed in our study overlap to various extents with those identified in similar previous studies. More precisely, our dimension of emotional and behavioral impact overlaps significantly with the bemotional characteristics factorQ and bthe immersion in hallucinationQ factor of 2 extant studies, respectively [9,10]. In addition, it combines elements of the factors of bintractabilityQ and binfluenceQ of another study [11]. Furthermore, our dimension of delusional elaboration corresponds roughly to the bcognitive interpretationQ and the bdelusionQ factors of other studies [9,11]. Moreover, the dimension of similarity to ordinary auditory perception matches well the brealityQ and bexternalityQ factors of 2 relevant studies [10,11]. Finally, the dimensions of severity and rate of intrusion in self-consciousness of our study jointly overlap with the bphysical characteristicsQ factor of another study [9]. The first and third factors may be viewed as distinct aspects of the intrinsic severity of auditory hallucinations. Their differential anamnestic correlates, especially with respect to duration of illness, indicate that in the course of schizophrenic disorders, the rate of auditory hallucinations’ intrusion in self-consciousness decreases, whereas, by contrast, their length increases. These findings are concordant with those of other studies whereby it has been shown that duration and length of auditory hallucinations in each occurrence remain unaffected by antipsychotic medications, in contrast to the frequency of their occurrence, which slows considerably in response to antipsychotic medications [5,24]. The negative correlation between the first factor and clinical depression stresses the adaptive character of auditory hallucinations in chronic patients— in the sense of supportiveness and mood-enhancing effects—and is in keeping with the findings of other studies [25,26]. Of special interest are our findings with respect to the second factor. The negative associations of this factor with duration of illness indicate that in earlier stages of psychotic disorders, patients’ emotional and behavioral involvement and concern are much stronger than in later stages, whereby affective blunting and apathy may
predominate. Furthermore, the strong positive association of this factor with overall severity of psychotic psychopathology (ie, BPRS score) suggests that the overall impact of auditory hallucinations on patients’ clinical picture is not brought about directly by their intrinsic severity, but rather that it is mediated by the influence they exert on patients’ affectivity and behavior. Various components of this factor have been found to respond well to antipsychotic medication, especially those of emotional impact and hallucinatory behavior, and, along with other components such as lack of volitional control, to be accessible to various psychotherapeutic treatment modalities [5,24-29]. With respect to the fourth factor, we should note its strong negative correlation with clinical depression, a finding supporting Maher’s [30] hypothesis about the formation of delusions as explanatory accounts of anomalous experiences—including auditory hallucinations—with tension and discomfort-reducing effects. Our fifth factor was found to correlate strongly with cognitive impairment. This cognitive impairment might also account for the defective mechanism of self-monitoring of internal speech hypothesized to underlie patients’ propensity to auditory hallucinations [31]. This factor, which subsumed the item of predominance of external over internal auditory hallucinations, was also correlated, though less strongly, with both age and duration of illness. However, to the extent that cognitive impairment reflects chronicity, this finding would provide evidence against the claim that in the course of psychotic illness auditory hallucinations become more binternalizedQ [8]. On the contrary, our findings on this score suggest that they become more bexternalizedQ and even more indistinguishable from normal auditory perceptual experiences. At any rate, only prospective longitudinal studies could settle this issue conclusively. In sum, the second and third factors extracted in our study correlated with short duration of illness, whereas the first, fourth, and fifth ones correlated with chronicity. The second factor correlated with clinical severity of patients’ current mental state, the fifth factor with severity of their cognitive impairment, whereas the first and fourth ones correlated with lower clinical depression despite patients’ chronicity. Besides its cross-sectional design, another limitation of the present study is that our sample was composed of schizophrenic inpatients only. Furthermore, the sample size, although acceptable for purposes of factor analysis, was not optimal to this end, lying at the lower acceptable limit. Finally, only confirmatory factor analysis testing clearly formulated in advance hypotheses could firmly establish the validity of its results. Overall, the findings of the present study contribute to the further elucidation of the major clinical dimensions of auditory hallucinations and the testing of their external validity. However, further research is warranted to examine their generalizability to other categories of mental disorders beyond the schizophrenic ones, especially to mood disorders with psychotic features.
P. Oulis et al. / Comprehensive Psychiatry 48 (2007) 337 – 342
341
Appendix A Characteristics of auditory hallucinations rating scales (during past week in most of their occurrences, most of the time) 1
2
3
Loudness (in comparison to subject’s other auditory experiences) Clarity: degree of understanding of their content Location: spatial specification of source of origin Intersubjectivity: expectation or belief that nearby people hear the bvoicesQ
Less loud
Equally loud
Louder
Unable to understand
Partial understanding
Full understanding
Unable to specify
Partial specification
Full specification
Only the patient hears them
All nearby people hear the voices
5 6
Duration (in each occurrence) Frequency
Less than 60 s Rarely
Some of the nearby people also hear the voices 2 to 30 min A few times every day
7
Objectivity: conviction about the reality of auditory sensory stimuli perceived by patient Homogeneity: similarity of auditory hallucinatory experience to the nonhallucinatory ones Length of utterances
Aware of hallucinations
Brief periods of doubt but generally convinced
More than 30 min Many times every day Unshakably convinced
Significantly different
Partially similar
Almost identical
A few words or brief sentences only No interaction between voices and thoughts
Mainly longer sentences Sometimes voices do comment or repeat or describe
Only or mainly in the second person Predominantly external hallucinations
Neither more prominent than the other Equally frequently internal and external hallucinations
Almost continuous utterances Frequent comments or repetitions of thoughts or actions Only or mainly in the third person Predominantly internal hallucinations
Mainly congruent
Both congruent and incongruent Moderate Succeeds only partly
1 2 3 4
8
9 10
Voices commenting on thoughts or actions
11
13
Second- and/or third-person auditory hallucinations Internal auditory hallucinations: inner voices, perceived with the vividness and concreteness characteristic of hallucinations but lacking external projection Congruence with affective state
14 15
Emotional impact Independence from volition
16
Hallucinatory behavior
17 18
Nonverbal auditory hallucinations Insight into auditory hallucinations
12
Absent or minimal Able to stop auditory hallucinations, perhaps by engaging in some activity Absent
Rarely Explains them in natural terms—bmy thoughts,Q billnessQ
Behaves as if hallucinated (lips move, whispers, looks around, replies, etc) Some times daily Unable to explain them
Mainly incongruent Marked Nearly or always unable to stop them
Has been engaged in actions with serious consequences due to auditory hallucinations Often daily Delusional explanation of hallucinations
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References [1] Bleuler E. In: Zinkin J, editor. Dementia praecox or the group of schizophrenias (1911). New York7 International Universities Press; 1950. p. 109. [2] Strauss JS. Hallucinations and delusions as points on continua function. Arch Gen Psychiatry 1969;21:581 - 6. [3] Aggernaes A. The experienced reality of hallucinations and other psychological phenomena. Acta Psychiatr Scand 1972;45:220 - 38. [4] Lowe GR. The phenomenology of hallucinations as an aid to differential diagnosis. Br J Psychiatry 1973;123:621 - 33. [5] Larkin AR. The form and content of schizophrenic hallucinations. Am J Psychiatry 1979;136:940 - 3. [6] Junginger J, Frame CL. Self-report of the frequency and phenomenology of verbal hallucinations. J Nerv Ment Dis 1985;173: 149 - 55. [7] Oulis P, Mavreas V, Mamounas J, Stefanis C. Clinical characteristics of auditory hallucinations. Acta Psychiatr Scand 1995;92:97 - 102. [8] Nayani TH, David AS. The auditory hallucination: a phenomenological survey. Psychol Med 1996;26:177 - 89. [9] Haddock G, Mc Carron J, Tarrier N, Faragher EB. Scales to measure dimensions of hallucinations and delusions: the psychotic symptoms rating scales (PSYRATS). Psychol Med 1999;29:879 - 89. [10] Singh G, Sharan P, Kulhara P. Phenomenology of hallucinations: a factor analytic approach. Psychiatry Clin Neurosci 2003;57:333 - 6. [11] Hayashi N, Igarashi Y, Suda K, Nakagawa S. Phenomenological features of auditory hallucinations and their symptomatological relevance. Psychiatry Clin Neurosci 2004;58:651 - 9. [12] American Psychiatric Association. Diagnostic and statistical manual of mental disorders. 4th ed. Washington7 American Psychiatric Press; 1994. [13] Wing JK, Cooper JE, Sartorius N. The measurement and classification of psychiatric symptoms. Cambridge7 Cambridge University Press; 1974. [14] Finke J. Halluzination. In: Mueller C, editor. Lexikon der Psychiatrie. 2nd ed. Berlin7 Springer; 1986. p. 319 - 23. [15] Spitzer M. Halluzinationen: Ein Beitrag zur allgemeinen und klinischen Psychopathologie. Berlin7 Springer; 1988. [16] World Health Organization. Schedules for the Assesment in Neuropsychiatry (SCAN) [glossary]. Geneva7 WHO; 1992.
[17] Overall JE. The Brief Psychiatric Rating Scale (BPRS): recent developments in ascertainment and scaling. Psychopharmacol Bull 1988;24:97 - 9. [18] Hamilton M. A rating scale for depression. J Neurol Neurosurg Psychiatry 1960;23:62 - 5. [19] Endicott J, Spitzer RL, Fleiss JL, Cohen J. The Global Assessment Scale: a procedure for measuring overall severity of psychiatric disturbance. Arch Gen Psychiatry 1976;33:711 - 66. [20] Folstein MF, Folstein SE, McHugh PR. Mini-Mental State: a practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res 1975;12:189 - 98. [21] Norussis MJ. SPSS for windows: professional statistics. Release 6.0. Chicago7 SPSS Inc; 1993. [22] Cohen J. Weighted kappa: nominal scale agreement with provision for scale disagreement or partial credit. Psychol Bull 1968;70:213 - 20. [23] Nunnally JC, Bernstein IH. Psychometric theory. 3rd ed. New York7 Mc Graw-Hill; 1994. p. 232. [24] Miller LJ. Qualitative changes in hallucinations. Am J Psychiatry 1996;153:265 - 7. [25] Benjamin LS. Is chronicity a function of the relationship between the person and the auditory hallucination? Schizophr Bull 1989; 15:291 - 310. [26] Miller LJ, Connor O’, DiPasquale T. Patients’ attitudes toward hallucinations. Am J Psychiatry 1993;150:584 - 8. [27] Hoen-Saric R, Gross M. Auditory hallucinations in schizophrenia: early changes under drug treatment and drug withdrawal. Am J Psychiatry 1968;124:1132 - 5. [28] Wiersma D, Jenner JA, van de Willige G, Spakman M, Nienhuis FJ. Cognitive behaviour therapy with coping training for persistent auditory hallucinations in schizophrenia: a naturalistic follow-up study of the durability of effects. Acta Psychiatr Scand 2001;103:393 - 9. [29] Jenner JA, Nienhuis FJ, van de Willige G, Wiersma D. bHittingQ voices of schizophrenia patients may lastingly reduce persistent auditory hallucinations and their burden: 18-month outcome of a randomized controlled trial. Can J Psychiatry 2006;51:169 - 77. [30] Maher B. Anomalous experience and delusional thinking: the logic of explanations. In: Oltmanns TF, Maher BA, editors. Delusional beliefs. New York7 Wiley; 1988. p. 15 - 33. [31] Frith C. The cognitive neuropsychology of schizophrenia. Hove7 Erlbaum; 1992.
Clinical dimensions of auditory hallucinations in schizophrenic disorders Panagiotis Oulisa,4, Rossetos Gournellisb, George Konstantakopoulosa, Thomas Matsoukasa, Panagiota G. Michalopouloub, Constantin Soldatosa, Lefteris Lykourasb b
a Department of Psychiatry, University of Athens, Eginition Hospital, 11528 Athens, Greece Second Department of Psychiatry, University of Athens, Attikon Hospital, 12462 Athens, Greece
Abstract Background: Auditory hallucinations occupy, along with delusional beliefs, the center stage of active or bpositiveQ psychotic clinical psychopathology. During the last decade, several sets of auditory hallucinations’ clinical features were subjected to multivariate statistical analyses to disclose major dimensions of psychotic patients’ overall hallucinatory experience and behavior. However, these studies failed, to a large extent, to provide satisfactory external validations of the thereby extracted factors. Methods: We investigated the major clinical dimensions of verbal auditory hallucinations in a sample of 100 inpatients with schizophrenic disorders. Patients (61 men and 39 women) were examined before the initiation of antipsychotic treatment and their assessment included 18 major clinical features of auditory hallucinations. Brief Psychiatric Rating Scale, Hamilton Depression Rating Scale, Global Assessment Scale, and Mini-Mental State Examination were used as external validators. Results: Principal component analysis resulted in the extraction of 5 factors interpreted as the dimensions of severity of auditory hallucinations, emotional and behavioral impact, rate of their intrusion in self-consciousness, delusional elaboration, and similarity to ordinary auditory perception, respectively. The second and third factors extracted in our study correlated with short duration of illness, whereas the first, fourth, and fifth ones correlated with chronicity. Our second factor correlated with clinical severity of patients’ current mental state, the fifth factor with severity of their cognitive impairment, and the first and fourth ones with lower clinical depression despite patients’ chronicity. Conclusion: The findings of our study contribute to the further elucidation of the major clinical dimensions of auditory hallucinations and the testing of their external validity. D 2007 Elsevier Inc. All rights reserved.
1. Introduction Auditory hallucinations occupy, along with delusional beliefs, the center stage of active or bpositiveQ psychotic clinical psychopathology and are, justifiably, incorporated into the diagnostic criteria of psychotic disorders, especially the schizophrenic ones. Their clinical complexity has been acknowledged long ago, at least since Bleuler’s [1] classic monograph on bthe group of schizophrenias,Q wherein various clinical dimensions of hallucinations were explicitly thematized such as intensity—loudness, clarity, outward projection—and reality value—objectivity for the patient. During the last 35 years, several clinical studies focused on various sets of auditory hallucinations’ features and found them to vary independently from 4 Corresponding author. Tel.: +30 2107289408; fax: +30 2107242020. E-mail address: [email protected] (P. Oulis). 0010-440X/$ – see front matter D 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.comppsych.2007.03.006
one another [2-8]. Moreover, during the last decade, several sets of auditory hallucinations’ clinical features were subjected to multivariate statistical analyses to disclose major dimensions of psychotic patients’ overall hallucinatory experience and behavior [9-11]. However, these studies did not provide satisfactory external validations of the extracted factors. For example, in the Haddock et al [9] study, only 1 of 3 factors exhibited external validity, whereas both factors in the study of Singh et al [10] correlated with patients’ Brief Psychiatric Rating Scale (BPRS) score. This fact renders their results—otherwise quite attractive because of their simplicity—rather arbitrary. The aim of the present study is to disclose clinically adequate and prognostically relevant dimensions of auditory hallucinations, taking care to test our solution for validity against a battery of external validators, such as demographic, anamnestic, and concurrent clinical ones.
338
P. Oulis et al. / Comprehensive Psychiatry 48 (2007) 337 – 342
2. Materials and methods From January 2005 to March 2006, 100 (61 men and 39 women) consecutive inpatients with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) [12] schizophrenic disorders and active auditory hallucinations on their admission at Eginition Hospital were included in the study. Active auditory hallucinations was defined as the experience of auditory hallucinations on admission to the hospital ward. All patients participating in the study gave written consent to this effect. The only exclusion criteria were patients’ unwillingness to participate in the study or their inability to this effect because of severe agitation or marked cognitive impairment. Patients’ mean age was 34.83 years (SD, 12.42 years) and their years of formal education were 11.20 (SD, 3.36). The mean duration of their illness was 8.98 years (SD, 7.68 years), with a mean number of psychiatric hospitalizations of 2.47 (SD, 2.12). With respect to clinical subtype, 59 were of the paranoid type, 37 of the undifferentiated type, and 4 of the disorganized types. Patients were examined within the first 3 days after their admission, before the initiation of any specifically antipsychotic treatment. At the time of their assessment, patients were receiving only minimal doses of benzodiazepines. Their examination by the first 3 authors (P.O., R.G., and G.K.) included the conduction of a semistructured interview, appropriate to the rating of 18 clinical characteristics of their auditory hallucinations by means of 3-point item scales (see Appendix A). Items selected for study were drawn from the relevant international literature [3-6,13-16]. Concomitantly, patients were also rated on a battery of wellknown clinical scales, including the BPRS [17], the Hamilton Depression Rating Scale (HDRS) [18], the Global Assessment Scale (GAS) [19], and, finally, the Mini-Mental State Examination (MMSE) [20]. Patients’ mean scores on these scales were as follows: BPRS, 58.93 (SD, 10.29); HDRS, 14.73 (SD, 6.68); GAS, 28.54 (SD, 5.96); and MMSE, 24.84 (SD, 3.38). SPSS software (SPSS, Chicago, IL) was used for the statistical analyses of data [21]. Patients’ scores on the item scales were subjected to factor analysis (principal components analysis), initially without rotation and thereafter with varimax rotation. Rotation did not change factors’ internal item composition. For the investigation of the external validity of the factorial solution obtained, Spearman q correlation coefficient values were computed between patients’ factor scores and their demographic and anamnestic data, their total scores on the above-mentioned 4 clinical scales, patients’ length of hospital stay, dosage of antipsychotic medications received during their index hospitalization, and modalities of disposition upon discharge from hospital. The sole exception was the dichotomous variable of sex for which 1-way nonparametric analysis of variance (Kruskal-Wallis) was performed. Interrater reliability of the auditory hallucinations item scales was tested in a subsample of 6 patients by means of
the weighted j statistic [22]. Finally, the extracted factors’ internal consistency was tested by means of Cronbach coefficient a [23].
3. Results The interrater reliability of the item scales was found quite satisfactory because their weighted j statistic values ranged from 0.65 (items of voices’ affective congruence and independence from volition) to 1.00 (for the items of lack of insight and objectivity). DSM-IV diagnostic reliability as well as BPRS, HDRS, and MMSE interrater reliability had been preliminary tested in a sample of 20 patients with schizophrenia with quite satisfactory reliability coefficient values ranging from 0.80 to 1.00. Principal components analysis resulted in the extraction of 8 factors with eigenvalues greater than unity, jointly accounting for 68.8% of the total variance. However, upon applying the scree plot test of eigenvalues we opted for a 5-factor solution, accounting for 52.4% of the total variance. The internal consistency of the 5 factors was also satisfactory, ranging from 0.73 to 0.86. Table 1 displays our main results. The first factor, interpreted as severity of auditory hallucinations, subsumed the items of hallucinations’ duration in each occurrence and the length of hallucinated utterances and was positively correlated to duration of illness and negatively to HDRS score. The second factor, interpreted as emotional and behavioral impact, comprised the items of hallucinatory behavior, affective congruence with hallucinatory content, emotional impact of hallucinatory occurrences, loudness of bvoices,Q patients’ expectation that bystanders also can hear their bvoicesQ as well as near-total independence of hallucinatory occurrences from patients’ volition. This factor was negatively correlated to duration of illness and positively to both BPRS and HDRS scores. Furthermore, the third factor, interpreted as rate of intrusion in self-consciousness, combined the items of frequency of hallucinatory occurrences and of voices commenting on patients’ current thoughts or actions, and was negatively correlated to age, duration of illness, and number of hospitalizations. Moreover, the fourth factor, interpreted as delusional elaboration, subsumed the items of lack of insight and unshakable belief in the actual existence of hallucinations’ emission source, being positively correlated to age and duration of illness as well as negatively correlated to number of hospitalizations and HDRS scores, respectively. Finally, the fifth factor, interpreted as similarity to normal auditory perception, included the items of homogeneity of hallucinations with ordinary auditory perception, patients’ ability to spatially localize their source, clarity of their content, predominance of external over internal hallucinations, predominance of third (over second) person hallucinations as well as absence of nonverbal hallucinations. This factor was negatively correlated to both GAS and MMSE scores
Table 1 Principal components analysis and correlations between factors and external validators Principal components analysis Factor I: severity of auditory hallucinations
Factor III: rate of intrusion in self-consciousness
Factor IV: delusional elaboration
Factor V: similarity to normal auditory perception
0.91
Hallucinatory behavior
0.85
Frequency
0.82
Lack of insight
0.81
Homogeneity
0.82
0.87
Affective congruence
0.82
Commenting voices
0.76
Belief in objectivity of hallucinatory emission source
0.55
Localization of emission source
0.78
Emotional impact Independence from volition Expectation of intersubjectivity
0.80 0.78
0.72 0.68
Loudness
0.45
Clarity of content Predominance of external vs internal hallucinations Predominance of third- vs second-person hallucinations Nonverbal auditory hallucinations
Only loadings N |0.40| are displayed Variance (%) 13.3
0.65
11.2
10.1
9.8
0.46
0.70
8.2
Correlations (r) between factors and external validators Duration of illness HDRS
0.41444 0.39444
Duration of illness BPRS HDRS
0.31444 0.42444 0.2944
Age Duration of illness No. of hospitalizations
0.30444 0.2944 0.40444
Age No. of hospitalizations HDRS
0.254 0.2844 0.38444
Age Duration of illness GAS MMSE
0.264 0.254 0.31444 0.42444
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Duration of each hallucinatory occurrence Length of hallucinatory sentences
Factor II: emotional and behavioral impact
4 P b .05. 44 P b .01. 444 P b .00.
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and positively to age and duration of illness. No significant differences were found with respect to patients’ sex or clinical subtype of schizophrenic disorders. Likewise, no significant correlations were found with respect to total doses of antipsychotic medications received during index hospitalization, length of index hospitalization, and modalities of patients’ disposition upon discharge from hospital. 4. Discussion The aim of the present study was to disclose major clinical dimensions of auditory hallucinations in a sample of 100 schizophrenic inpatients and to test for their external validity. The 5 dimensions of auditory hallucinations disclosed in our study overlap to various extents with those identified in similar previous studies. More precisely, our dimension of emotional and behavioral impact overlaps significantly with the bemotional characteristics factorQ and bthe immersion in hallucinationQ factor of 2 extant studies, respectively [9,10]. In addition, it combines elements of the factors of bintractabilityQ and binfluenceQ of another study [11]. Furthermore, our dimension of delusional elaboration corresponds roughly to the bcognitive interpretationQ and the bdelusionQ factors of other studies [9,11]. Moreover, the dimension of similarity to ordinary auditory perception matches well the brealityQ and bexternalityQ factors of 2 relevant studies [10,11]. Finally, the dimensions of severity and rate of intrusion in self-consciousness of our study jointly overlap with the bphysical characteristicsQ factor of another study [9]. The first and third factors may be viewed as distinct aspects of the intrinsic severity of auditory hallucinations. Their differential anamnestic correlates, especially with respect to duration of illness, indicate that in the course of schizophrenic disorders, the rate of auditory hallucinations’ intrusion in self-consciousness decreases, whereas, by contrast, their length increases. These findings are concordant with those of other studies whereby it has been shown that duration and length of auditory hallucinations in each occurrence remain unaffected by antipsychotic medications, in contrast to the frequency of their occurrence, which slows considerably in response to antipsychotic medications [5,24]. The negative correlation between the first factor and clinical depression stresses the adaptive character of auditory hallucinations in chronic patients— in the sense of supportiveness and mood-enhancing effects—and is in keeping with the findings of other studies [25,26]. Of special interest are our findings with respect to the second factor. The negative associations of this factor with duration of illness indicate that in earlier stages of psychotic disorders, patients’ emotional and behavioral involvement and concern are much stronger than in later stages, whereby affective blunting and apathy may
predominate. Furthermore, the strong positive association of this factor with overall severity of psychotic psychopathology (ie, BPRS score) suggests that the overall impact of auditory hallucinations on patients’ clinical picture is not brought about directly by their intrinsic severity, but rather that it is mediated by the influence they exert on patients’ affectivity and behavior. Various components of this factor have been found to respond well to antipsychotic medication, especially those of emotional impact and hallucinatory behavior, and, along with other components such as lack of volitional control, to be accessible to various psychotherapeutic treatment modalities [5,24-29]. With respect to the fourth factor, we should note its strong negative correlation with clinical depression, a finding supporting Maher’s [30] hypothesis about the formation of delusions as explanatory accounts of anomalous experiences—including auditory hallucinations—with tension and discomfort-reducing effects. Our fifth factor was found to correlate strongly with cognitive impairment. This cognitive impairment might also account for the defective mechanism of self-monitoring of internal speech hypothesized to underlie patients’ propensity to auditory hallucinations [31]. This factor, which subsumed the item of predominance of external over internal auditory hallucinations, was also correlated, though less strongly, with both age and duration of illness. However, to the extent that cognitive impairment reflects chronicity, this finding would provide evidence against the claim that in the course of psychotic illness auditory hallucinations become more binternalizedQ [8]. On the contrary, our findings on this score suggest that they become more bexternalizedQ and even more indistinguishable from normal auditory perceptual experiences. At any rate, only prospective longitudinal studies could settle this issue conclusively. In sum, the second and third factors extracted in our study correlated with short duration of illness, whereas the first, fourth, and fifth ones correlated with chronicity. The second factor correlated with clinical severity of patients’ current mental state, the fifth factor with severity of their cognitive impairment, whereas the first and fourth ones correlated with lower clinical depression despite patients’ chronicity. Besides its cross-sectional design, another limitation of the present study is that our sample was composed of schizophrenic inpatients only. Furthermore, the sample size, although acceptable for purposes of factor analysis, was not optimal to this end, lying at the lower acceptable limit. Finally, only confirmatory factor analysis testing clearly formulated in advance hypotheses could firmly establish the validity of its results. Overall, the findings of the present study contribute to the further elucidation of the major clinical dimensions of auditory hallucinations and the testing of their external validity. However, further research is warranted to examine their generalizability to other categories of mental disorders beyond the schizophrenic ones, especially to mood disorders with psychotic features.
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Appendix A Characteristics of auditory hallucinations rating scales (during past week in most of their occurrences, most of the time) 1
2
3
Loudness (in comparison to subject’s other auditory experiences) Clarity: degree of understanding of their content Location: spatial specification of source of origin Intersubjectivity: expectation or belief that nearby people hear the bvoicesQ
Less loud
Equally loud
Louder
Unable to understand
Partial understanding
Full understanding
Unable to specify
Partial specification
Full specification
Only the patient hears them
All nearby people hear the voices
5 6
Duration (in each occurrence) Frequency
Less than 60 s Rarely
Some of the nearby people also hear the voices 2 to 30 min A few times every day
7
Objectivity: conviction about the reality of auditory sensory stimuli perceived by patient Homogeneity: similarity of auditory hallucinatory experience to the nonhallucinatory ones Length of utterances
Aware of hallucinations
Brief periods of doubt but generally convinced
More than 30 min Many times every day Unshakably convinced
Significantly different
Partially similar
Almost identical
A few words or brief sentences only No interaction between voices and thoughts
Mainly longer sentences Sometimes voices do comment or repeat or describe
Only or mainly in the second person Predominantly external hallucinations
Neither more prominent than the other Equally frequently internal and external hallucinations
Almost continuous utterances Frequent comments or repetitions of thoughts or actions Only or mainly in the third person Predominantly internal hallucinations
Mainly congruent
Both congruent and incongruent Moderate Succeeds only partly
1 2 3 4
8
9 10
Voices commenting on thoughts or actions
11
13
Second- and/or third-person auditory hallucinations Internal auditory hallucinations: inner voices, perceived with the vividness and concreteness characteristic of hallucinations but lacking external projection Congruence with affective state
14 15
Emotional impact Independence from volition
16
Hallucinatory behavior
17 18
Nonverbal auditory hallucinations Insight into auditory hallucinations
12
Absent or minimal Able to stop auditory hallucinations, perhaps by engaging in some activity Absent
Rarely Explains them in natural terms—bmy thoughts,Q billnessQ
Behaves as if hallucinated (lips move, whispers, looks around, replies, etc) Some times daily Unable to explain them
Mainly incongruent Marked Nearly or always unable to stop them
Has been engaged in actions with serious consequences due to auditory hallucinations Often daily Delusional explanation of hallucinations
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