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Correlations over time between dysphoric mood and symptomatology in schizophrenia
Correlations Over Time Between Dysphoric and Symptomatology in Schizophrenia RossM.G.
Norman
Monthly assessments of depression, anxiety, and positive and negative symptoms of schizophrenia were performed on 52 schizophrenic patients over periods ranging from 12 to 29 months. Data were analyzed to assess the extent to which symptoms of dysphoria (anxiety and depression) were more strongly related to negative or positive symptoms of schizophrenia.
I
Mood
and Ashok K. Malla Consistent with past research using comparisons across subjects, the current longitudinal data show that there is a more consistent relationship between dysphoria and positive rather than negative symptoms. Copyright 0 1994by W.B. Saunders Company
T HAS BEEN SUGGESTED that negative symptoms in schizophrenia may be a reflection of depression.‘J Unfortunately, a bias may have been present in past research relevant to this possibility in that ratings of patients’ level of depression and negative symptoms have been made by the same rater.3-5 Barnes et al6 report finding no relationship between scores on a self-report measure of depression (the Beck Depression Inventory [BDI]) and negative symptomatology, but they did find evidence that depression was related to the presence of at least some positive symptomatology. It has also been suggested that anxiety may be related to negative symptomatology.2~7~8 In a recent study,9 we presented data relating selfreport measures of depression and anxiety to independent assessments of positive and negative symptoms (in a group of 95 patients suffering from schizophrenia). We found that individual differences in both anxiety and depression were in fact more closely related to individual differences in positive rather than in negative symptomatology. In addition, we found that various measures of anxiety and depression appeared to show equal convergent validity with one another. This latter finding is consistent with results in other populations,lOJ1 and suggests that for many purposes it may be meaning-
ful to think of anxiety and depression as reflecting a general construct of negative affectivity or dysphoria. Past studies on the relationship between dysphoria and negative and positive symptoms of schizophrenia have focused on comparisons across patients using cross-sectional data. They address the question of whether patients who differ in their level of dysphoria also differ in their level of positive or negative symptomatology. The results of such studies are often incorrectly interpreted as reflecting the relationship between the symptoms within individual patients. Patterns of correlations between symptoms across patients do not necessarily reflect a temporal relationship between the same symptoms within individual patients.i2 Research in other domains indicates that different patterns of interrelationships between symptoms can be found for comparisons across individuals as opposed to comparisons across time within individuals.i3 Therefore, the question arises as to whether dysphoria covaries over time more strongly with positive or negative symptoms. In this report, we present the results from a longitudinal study of patients with schizophrenia, which assessed the temporal relationships between dysphoria and positive and negative symptoms.
From the Department of Psychiatry, University of Western Ontario. London, Ontario, Canada. Supported by grants from the Department of Psychiatry, University of Western Ontario, and the Lipjohn London Neurosciences Program. Address reprint requests to Ross M.G. Norman, Ph.D., Room 126, WMCH Bldg, Community Rehabilitation Program, Victoria Hospital, 392 South St, London, Ontario, Canada N6A 4G5. Copyright 0 1994 by W.B. Saunders Company OOIO-44OXl94/3501-0012$03.OOiO
Subjects were recruited from outpatient clinics at Victoria Hospital and London Psychiatric Hospital in London, Ontario, Canada, as well as at North Bay Psychiatric Hospital in North Bay, Ontario. Inclusion and exclusion criteria for patients with schizophrenia were the same as those reported elsewhere.9 At the time of each patient’s entry into the study, demographic information such as age, gender, marital status, educational background, and employment history were recorded. In addition, information was collected concerning current neuroleptic medication, total number of past admissions for psychiatric treatment, and
METHOD
34
Comprehensive Psychiatry, Vol. 35, No. 1 (January/February),
1994: pp 34-38
DYSPHORIA AND SYMPTOMATOLOGY
length of time since the most recent discharge from hospital. Information concerning medication and treatment history was recorded from patient charts and confirmed with clinicians. Patients were seen on a monthly basis for periods ranging between 12 and 29 months. Variations in the length of time that patients consideration
35
IN SCHIZOPHRENIA
were evaluated were determined by funding rather than by patient characteristics. During
each session. symptomatology was assessed by both selfreport questionnaires and ratings completed by the interviewer. Questionnaires included the BDIIJ as a measure of depression. and the Self-Evaluation Questionnaire (SEQ). a measure of anxiety developed by Spielberger.ls With reference to the completion of the self-report inventories, it is important to note that all subjects in the current sample were outpatients who were functioning cognitively at a level that enabled them to live in the community. Research staff were permitted to explain occasionally the wording of a question on the inventories, but not to examine the patient’s response to the questions. If the interviewer had reason to believe that a patient was incapable of reliably completing any of the self-report inventories used, then that patient was not included in the final sample. Five patients were removed from the study for this reason. In addition, each subject was interviewed by a carefully trained interviewer who rated the patient for level of positive and negative symptoms. The Scale for the Assessment of Positive Symptoms (SAPS)“) and the Scale for the Assessment of Negative Symptoms (SANS)” were used for these ratings. The SAPS consists of 34 items and is divided into the following four subscales: hallucinations, delusions. bizarre behavior. and formal thought disorder. The SANS consists of 35 items and has five subscales, as follows: affective flattening or blunting, alogia. apathy, asociality. and inattention. Interrater reliabilities for the SAPS and SANS were established by calculating intraclass correlation coefficients (ICCs) for 15 patients who were assessed by an interviewer and one of the senior investigators (R.N. or A.M.). The total score on the SAPS yielded an ICC of .Y4. and the ICC for total SANS score was 24. Global ratings for subscales of the SANS and SAPS had an average ICC of .83. and ranged from .hl for alogia to .98 for both hallucinations and delusions. All ICCs were significant at a minimum of the .005 level. It is important to note that interviewers were blind with regard to patient scores on the measures of depression and anxiety when completing the ratings of positive and negative symptoms. This. of course. eliminates the risk of the symptoms ratings being influenced by knowledge of depression or anxiety scores. Recent studies on the structure of symptomatology in schizophrenia as measured by instruments such as the SAPS and SANS suggest that it is best conceived of as involving the following three syndromes: reality distortion, disorganization. and psychomotor poverty. ‘K-20The reality distortion
syndrome consists of hallucinations and delusions. Disorganization refers to disorganized thought processes such as tangentiality, derailment, pressure of speech, distractibility, and inappropriate affect. Psychomotor poverty syndrome refers to poverty of speech. decreased spontaneous movement. and blunting of affect (such as lack of facial expres-
sion, paucity of expressive gestures. affective nonresponsivity, lack of vocal inflection). A factor analysis of symptoms rated with the SAPS and SANS for this sample revealed three separate factors that corresponded to the three syndromes previously described. We therefore conducted additional analyses exploring the relationship of each of these syndromes with symptoms of dysphoria.
RESULTS
Characteristics of the sample are outlined in Table 1. A total of 55 patients were assessed for at least 12 monthly assessments. Approximately three fourths of the sample were men, and the average age was just under 38 years. The majority of patients had a minimum of a high school education, but most were unemployed. There was an average of three previous psychiatric hospitalizations per patient, and the average chlorpromazine equivalent dosage of their medication was 412 mgid. Total SAPS and SANS scores were calculated by adding the subscale global ratings. The mean score on the SAPS at the time of first assessment was 1.69 with a range from zero to 8, and for the SANS the mean score was 3.3 with a range from zero to 15. On the BDI the mean score was 11.5 with a range from zero to 39. and
Table 1. Characteristics
of Sample (n = 55)
Gender Males. 72.7% Females, 27.3% Age W) Average, 37.8 Range, 21 to 53 No. of psychiatric admissions Average, 3 Range, 1 to 9 Educational level Incomplete primary school, 3.6% Primary completed, but no secondary, 1.8% Incomplete secondary, 29.8% Secondary completed, but no postsecondary, 15.7% Postsecondary (college or university), but incomplete, 25.4% Postsecondary completed, 23.7% Employment Unemployed, 54.5% Casual and part-time employed, 20% Employed full-time, 20% Student, 3.6% Homemaker, 1.8% Medication (chlorpromazine daily equivalent) Average, 412 mg Range, 20 to 2,375 mg
NORMAN AND MALLA
36
for the SEQ the mean was 35.2 with a range from 0 to 67. There were three patients who showed no change in level of symptomatology over the course of the study. These patients were omitted from the sample in the following analyses, leaving a net sample of 52. For those cases in which there were significant serial correlations within symptoms over time, the correction to the #suggested by Holtzman*l was adopted for assessing the significance of correlations between symptoms. A p value of .025 or less, one-tailed, was used for the identification of significant correlations. Parallel to our earlier findings involving comparisons across 95 patients,9 in this study we found evidence of a strong relationship between anxiety and depression over time. The majority of patients (57.7%) showed a significant correlation across monthly assessments between the BDI and SEQ, and the average value of the correlation for all subjects was .68. In the examination of the relationships between dysphoria (depression and anxiety) and positive and negative symptoms, we initially calculated four correlations for each patient. These were the correlations across time of scores on the BDI and SEQ with total scores on the SAPS and SANS. The percentage of patients whose data showed significant (P < .025) correlations between each pair of symptoms is presented in the top portion of Table 2. Contrasts using a test of differences in proportions showed that there was a greater proportion of significant correlations with the SAPS than with the SANS for both the BDI and SEQ (x2 (1) = 8.89, P < .Ol, x2 (1) = 4.29, P < .05, respectively). We calculated the number of patients for whom there was a significant correlation between the BDI or SEQ and each of the SAPS Table 2. Percentage of Significant Correlations of Dysphoria With Positive and Negative Symptoms (n = 52) Symptom
Measure
Depression
(BDI)
Anxiety (SEQ)
25%
SAPS total
36.5%
SANS total
11.5%
Reality distortion
29.2%
25%
Disorganization
19.2%
11.5%
Psychomotor poverty
13.5%
5.7%
9.6%
and SANS. This provides a more general index of the differential relationship between dysphoria and positive and negative symptoms. The figure was 48.1% for the SAPS and 17.3% for the SANS; the two proportions differed significantly (x2 (1) = 11.18, P < .OOl). The differential rate of association between measures of dysphoria and positive and negative symptoms could result from there being less variation over time in negative symptoms than in positive symptoms. If more patients show restrictive range on negative symptoms, then this would mean that the lower proportion of significant correlations with the SANS essentially reflects a statistical artifact. Further examination of our data show that this is not the case. We calculated the percentage of patients who over time showed a range of scores on the SAPS and SANS equal to or greater than 10% of the maximum possible range. In actual fact, a larger number of patients met this criterion for the SANS (47 patients) than for the SAPS (23 patients; see also Malla et a1.22).Furthermore, when we restricted our examination of correlates for each of the SAPS and SANS to those who met this range criterion, there was still a significantly higher proportion of significant correlations of the BDI and SEQ with the SAPS than with the SANS (47.8% v 12.7% and 39% v 10.6%, respectively). As indicated earlier, recent research suggests that the symptoms assessed by the SAPS and SANS actually reflect three underlying dimensions of symptomatology in schizophrenia, i.e., reality distortion, disorganization, and psychomotor poverty. Following the guidelines from previous research and factor analysis of symptoms from this sample, we divided the items to provide an index of each of these three syndromes. (Information regarding the items used for each of the composite scores can be obtained by writing the authors.) We then calculated the percentage of significant correlations for the BDI and SEQ with each of the syndromes; the results are presented in the lower part of Table 2. It can be seen that the highest percentage of significant correlations was found for the reality distortion syndrome, followed by the disorganization syndrome, and the lowest percentage occurred for the psychomotor pov-
DYSPHORIA
AND SYMPTOMATOLOGY
IN SCHIZOPHRENIA
erty syndrome. When proportions of significant correlations are contrasted, only the difference between reality distortion and psychomotor poverty is significant for the SEQ (x2 (1) = 7.23, P < .Ol). For the BDI, this difference closely approaches significance at the .05 level (x’ (1) = 3.71). It should be noted that the percentage of significant positive correlations that would be expected to occur by chance in each cell of Table 2 is 2.5%. In almost all cells (with the possible exception of the relationship between the SEQ and psychomotor poverty), the percentage of significant correlations observed is at least several magnitudes greater than chance expectation. We contrasted the number of significant dysphoriaisymptom correlations that were found for patient groupings defined by gender, as well as median splits on such variables as age, number of previous psychiatric admissions, and chlorpromazine equivalence dosage of neuroleptic medication. The results provided no evidence of any of these variables being related to the number of significant correlations. There was no evidence that patients who were receiving anticholinergic medication showed a different proportion of significant correlations than those who were not receiving anticholinergics. DISCUSSION
It has been argued that there is considerable overlap between negative symptoms and depression.‘,’ As we have suggested elsewhere,9 the data that have been presented in favor of this argument are characterized either by there being no appropriate comparison group,’ or by observational ratings of depression and negative symptoms being performed by the same raters.’ On an observational level, many of the behaviors attributed to negative symptoms and depression, such as slowness, withdrawal, decrease in sexual drive, etc., are indistinguishable. Our finding of a longitudinal relationship between negative symptoms and depression for a very modest proportion of patients is consistent with two previous reports of cross-sectional data using self-report measures of depression.b,y The contrast between studies suggesting a strong
37
relationship between depression and negative symptoms and those suggesting a very modest or no relationship cannot be explained entirely by the use of rating scale versus self-report indices of depression. There are now several reports using observer ratings of both depression and negative symptoms that also conclude that there is little if any relationship between the two.“,3.8.‘” The general weight of evidence is therefore suggests that depression and negative symptoms are largely independent. On the other hand, our longitudinal data add further support to the argument that dysphoria (including both d epression and anxiety) is more strongly related to positive symptoms. This is consistent with previous cross-sectional studies using self-report measures of dysphoria.b,y It should also be noted that Hirsch et al.,“” in reviewing evidence from several studies using both rating scales and self-report measures, suggest that there is evidence of a more reliable relationship of depression with psychotic or positive symptoms rather than with negative symptoms. Such findings are consistent with the suggestion by several investigators that dysphoric mood is often associated with an increase in the likelihood of positive psychotic features of schizophrenia.‘4-‘6 In individuals vulnerable to schizophrenia, dysphoria may serve as a mediator in the development of positive symptoms in response to psychosocial stressors 27.18 Our results suggest that the relationship between dysphoria and reality distortion (hallucinations and delusions) is the most robust. It is tempting to speculate that this closer relationship between dysphoria and reality distortion may have pathophysiologic significance. The reality distortion syndrome is reported to be related to dysfunction in the left medial temporal lobe’” and is thus related closely to the rest of the limbic system, which is recognized as playing an important role in emotional responses. ACKNOWLEDGMENT Assistance was provided by North Nay Psychiatric Hospital. Dr. Peter Williamson and the staff of the active treatment unit of London Psychiatric Hospital, and the case managers of the Community Rehabilitation Program of Victoria Hospital.
38
NORMAN AND MALLA
REFERENCES 1. Sommers AA. ‘Negative symptoms’: conceptual and methodological problems. Schizophr Bull 1985;11:364-379. 2. Zubin J. Negative symptoms: are they indigenous to schizophrenia? Schizophr Bull 1985;11:461-470. 3. Prosser ES, Csernansky JG, Kaplan J, Thiemann S, Becker TJ, Hollister LE. Depression, Parkinsonian symptoms, and negative symptoms in schizophrenics treated with neuroleptics. J Nerv, Ment Dis 1987;175:100-105. 4. Kulhara P, Avasthi A, Chadda R, Chandiramani K, Mattoo SK, Joseph S. Negative and depressive symptoms in schizophrenia. Br J Psychiatry 1989;154:207-211. 5. Lindenmayer JP, Kay SR. Depression, affect and negative symptoms in schizophrenia. Br J Psychiatry 1989; 155(7 Suppl):108-114. 6. Barnes TR. Curson DA, Liddle PF, Pate1 M. The nature and prevalence of depression in chronic schizophrenic inpatients. Br J Psychiatry 1989;154:486-491. 7. Siris SG, Adam F, Cohen M, Mandeli J, Aronson A, Casey E. Post psychotic depression and negative symptoms. An investigation of syndromal overlap. Am J Psychiatry 1988;145:1532-1537. 8. McKenna PJ, Lund CE, Mortimer AM. Negative symptoms: Relationships to other schizophrenic symptom classes. Br J Psychiatry 1989;155(7 Suppl):104-107. 9. Norman RMG, Malla AK. Dysphoric mood and symptomatology in schizophrenia. Psycho1 Med 1991;21:897-903. 10. Watson D, Clark LA. Negative affectivity: the disposition to experience aversive emotional states. Psycho1 Bull 1984;96:465-490. 11. Wolfe VV, Finch AJ Jr, Saylor CF, Blount RL, Pallmeyer TP, Carek DJ. Negative affectivity in children: a multitrait-multimethod investigation. J Consult Clin Psychol 1987;55:245-250. 12. Valsiner J. Between groups and individuals. Psychologists’ and lay persons’ interpretation of correlational findings. In: Valsiner J (ed): The Individual Subject and Scientific Psychology. New York, NY: Plenum, 1986:113151. 13. Gonder-Frederick LA, Cox DJ, Bobbitt SA, Pennebaker JW. Mood changes associated with blood glucose fluctuations in insulin-dependent diabetes mellitus. Health Psycho1 1989;8:45-59. 14. Beck AT. Beck Depression Inventory. New York, NY: Harcourt Brace Jovanovich, 1978. 15. Spielberger CD, Gorsuch RL, Lushene R. Self-
Evaluation Questionnaire. Palo Alto, CA: Consulting Psychologists, 1968. 16. Andreasen NC. The Scale for the Assessment of Positive Symptoms. (SAPS). Iowa City, IA: University of Iowa, 1984. 17. Andreasen NC. The Scale for the Assessment of Negative Symptoms (SANS). Iowa City, IA: University of Iowa, 1983. 18. Kulhara P. Kota SK, Joseph S. Positive and negative subtypes of schizophrenia: a study from India. Acta Psychiatr Stand 1986;74:353-359. 19. Liddle PF, Barnes TR. Syndromes of chronic schizophrenia. Br J Psychiatry 1990;157:558-561. 20. Arndt S. Alliger RJ, Andreasen NC. The distinction of positive and negative symptoms: the failure of a twodimensional model. Br J Psychiatry 1991;158:317-322. 21. Holtzman WH. Statistical models for the study of change in the single case. In: Harris CW (ed): Problems in Measuring Change. Madison. WI: University of Wisconsin Press, 1963:199-211. 22. Malla AK, Norman RMG, Williamson P. Stability of positive and negative symptoms in schizophrenia. Can J Psychiatry. In press. 23. Hirsch SR, Jolley AG, Barnes TRE, Liddle PF, Curson DA, Pate1 A. et al. Dysphoric and depressive symptoms in chronic schizophrenia. Schizopr Res 1989;2:259264. 24. Foulds G, Bedford A. Hierarchy of classes of personal illness. Psycho1 Med 1975;5:181-192. 25. Slade P. The effects of systematic desensitization on auditory hallucinations. Behav Res Ther 1971;10:85-91. 26. Kirkpatrick 8, Buchanan RW, Waltrip RW, Jauch D, Carpenter WT. Brief communication: diazepam treatment of early symptoms of schizophrenic relapse. J Nerv Ment Dis 1989;177:52-53. 27. Norman RMG, Malla AK. Stressful life events and schizophrenia. I. A review of the research. Br J Psychiatry. In press. 28. Norman RMG, Malla AK. Stressful live events and schizophrenia. II. Conceptual and methodological issues. Br J Psychiatry. In press. 29. Liddle PF, Friston KJ, Frith CD, Hirsch SR, Jones T, Frackowiak RSJ. Patterns of cerebral blood flow in schizophrenia. Br J Psychiatry 1992;160:179-186.
Norman
Monthly assessments of depression, anxiety, and positive and negative symptoms of schizophrenia were performed on 52 schizophrenic patients over periods ranging from 12 to 29 months. Data were analyzed to assess the extent to which symptoms of dysphoria (anxiety and depression) were more strongly related to negative or positive symptoms of schizophrenia.
I
Mood
and Ashok K. Malla Consistent with past research using comparisons across subjects, the current longitudinal data show that there is a more consistent relationship between dysphoria and positive rather than negative symptoms. Copyright 0 1994by W.B. Saunders Company
T HAS BEEN SUGGESTED that negative symptoms in schizophrenia may be a reflection of depression.‘J Unfortunately, a bias may have been present in past research relevant to this possibility in that ratings of patients’ level of depression and negative symptoms have been made by the same rater.3-5 Barnes et al6 report finding no relationship between scores on a self-report measure of depression (the Beck Depression Inventory [BDI]) and negative symptomatology, but they did find evidence that depression was related to the presence of at least some positive symptomatology. It has also been suggested that anxiety may be related to negative symptomatology.2~7~8 In a recent study,9 we presented data relating selfreport measures of depression and anxiety to independent assessments of positive and negative symptoms (in a group of 95 patients suffering from schizophrenia). We found that individual differences in both anxiety and depression were in fact more closely related to individual differences in positive rather than in negative symptomatology. In addition, we found that various measures of anxiety and depression appeared to show equal convergent validity with one another. This latter finding is consistent with results in other populations,lOJ1 and suggests that for many purposes it may be meaning-
ful to think of anxiety and depression as reflecting a general construct of negative affectivity or dysphoria. Past studies on the relationship between dysphoria and negative and positive symptoms of schizophrenia have focused on comparisons across patients using cross-sectional data. They address the question of whether patients who differ in their level of dysphoria also differ in their level of positive or negative symptomatology. The results of such studies are often incorrectly interpreted as reflecting the relationship between the symptoms within individual patients. Patterns of correlations between symptoms across patients do not necessarily reflect a temporal relationship between the same symptoms within individual patients.i2 Research in other domains indicates that different patterns of interrelationships between symptoms can be found for comparisons across individuals as opposed to comparisons across time within individuals.i3 Therefore, the question arises as to whether dysphoria covaries over time more strongly with positive or negative symptoms. In this report, we present the results from a longitudinal study of patients with schizophrenia, which assessed the temporal relationships between dysphoria and positive and negative symptoms.
From the Department of Psychiatry, University of Western Ontario. London, Ontario, Canada. Supported by grants from the Department of Psychiatry, University of Western Ontario, and the Lipjohn London Neurosciences Program. Address reprint requests to Ross M.G. Norman, Ph.D., Room 126, WMCH Bldg, Community Rehabilitation Program, Victoria Hospital, 392 South St, London, Ontario, Canada N6A 4G5. Copyright 0 1994 by W.B. Saunders Company OOIO-44OXl94/3501-0012$03.OOiO
Subjects were recruited from outpatient clinics at Victoria Hospital and London Psychiatric Hospital in London, Ontario, Canada, as well as at North Bay Psychiatric Hospital in North Bay, Ontario. Inclusion and exclusion criteria for patients with schizophrenia were the same as those reported elsewhere.9 At the time of each patient’s entry into the study, demographic information such as age, gender, marital status, educational background, and employment history were recorded. In addition, information was collected concerning current neuroleptic medication, total number of past admissions for psychiatric treatment, and
METHOD
34
Comprehensive Psychiatry, Vol. 35, No. 1 (January/February),
1994: pp 34-38
DYSPHORIA AND SYMPTOMATOLOGY
length of time since the most recent discharge from hospital. Information concerning medication and treatment history was recorded from patient charts and confirmed with clinicians. Patients were seen on a monthly basis for periods ranging between 12 and 29 months. Variations in the length of time that patients consideration
35
IN SCHIZOPHRENIA
were evaluated were determined by funding rather than by patient characteristics. During
each session. symptomatology was assessed by both selfreport questionnaires and ratings completed by the interviewer. Questionnaires included the BDIIJ as a measure of depression. and the Self-Evaluation Questionnaire (SEQ). a measure of anxiety developed by Spielberger.ls With reference to the completion of the self-report inventories, it is important to note that all subjects in the current sample were outpatients who were functioning cognitively at a level that enabled them to live in the community. Research staff were permitted to explain occasionally the wording of a question on the inventories, but not to examine the patient’s response to the questions. If the interviewer had reason to believe that a patient was incapable of reliably completing any of the self-report inventories used, then that patient was not included in the final sample. Five patients were removed from the study for this reason. In addition, each subject was interviewed by a carefully trained interviewer who rated the patient for level of positive and negative symptoms. The Scale for the Assessment of Positive Symptoms (SAPS)“) and the Scale for the Assessment of Negative Symptoms (SANS)” were used for these ratings. The SAPS consists of 34 items and is divided into the following four subscales: hallucinations, delusions. bizarre behavior. and formal thought disorder. The SANS consists of 35 items and has five subscales, as follows: affective flattening or blunting, alogia. apathy, asociality. and inattention. Interrater reliabilities for the SAPS and SANS were established by calculating intraclass correlation coefficients (ICCs) for 15 patients who were assessed by an interviewer and one of the senior investigators (R.N. or A.M.). The total score on the SAPS yielded an ICC of .Y4. and the ICC for total SANS score was 24. Global ratings for subscales of the SANS and SAPS had an average ICC of .83. and ranged from .hl for alogia to .98 for both hallucinations and delusions. All ICCs were significant at a minimum of the .005 level. It is important to note that interviewers were blind with regard to patient scores on the measures of depression and anxiety when completing the ratings of positive and negative symptoms. This. of course. eliminates the risk of the symptoms ratings being influenced by knowledge of depression or anxiety scores. Recent studies on the structure of symptomatology in schizophrenia as measured by instruments such as the SAPS and SANS suggest that it is best conceived of as involving the following three syndromes: reality distortion, disorganization. and psychomotor poverty. ‘K-20The reality distortion
syndrome consists of hallucinations and delusions. Disorganization refers to disorganized thought processes such as tangentiality, derailment, pressure of speech, distractibility, and inappropriate affect. Psychomotor poverty syndrome refers to poverty of speech. decreased spontaneous movement. and blunting of affect (such as lack of facial expres-
sion, paucity of expressive gestures. affective nonresponsivity, lack of vocal inflection). A factor analysis of symptoms rated with the SAPS and SANS for this sample revealed three separate factors that corresponded to the three syndromes previously described. We therefore conducted additional analyses exploring the relationship of each of these syndromes with symptoms of dysphoria.
RESULTS
Characteristics of the sample are outlined in Table 1. A total of 55 patients were assessed for at least 12 monthly assessments. Approximately three fourths of the sample were men, and the average age was just under 38 years. The majority of patients had a minimum of a high school education, but most were unemployed. There was an average of three previous psychiatric hospitalizations per patient, and the average chlorpromazine equivalent dosage of their medication was 412 mgid. Total SAPS and SANS scores were calculated by adding the subscale global ratings. The mean score on the SAPS at the time of first assessment was 1.69 with a range from zero to 8, and for the SANS the mean score was 3.3 with a range from zero to 15. On the BDI the mean score was 11.5 with a range from zero to 39. and
Table 1. Characteristics
of Sample (n = 55)
Gender Males. 72.7% Females, 27.3% Age W) Average, 37.8 Range, 21 to 53 No. of psychiatric admissions Average, 3 Range, 1 to 9 Educational level Incomplete primary school, 3.6% Primary completed, but no secondary, 1.8% Incomplete secondary, 29.8% Secondary completed, but no postsecondary, 15.7% Postsecondary (college or university), but incomplete, 25.4% Postsecondary completed, 23.7% Employment Unemployed, 54.5% Casual and part-time employed, 20% Employed full-time, 20% Student, 3.6% Homemaker, 1.8% Medication (chlorpromazine daily equivalent) Average, 412 mg Range, 20 to 2,375 mg
NORMAN AND MALLA
36
for the SEQ the mean was 35.2 with a range from 0 to 67. There were three patients who showed no change in level of symptomatology over the course of the study. These patients were omitted from the sample in the following analyses, leaving a net sample of 52. For those cases in which there were significant serial correlations within symptoms over time, the correction to the #suggested by Holtzman*l was adopted for assessing the significance of correlations between symptoms. A p value of .025 or less, one-tailed, was used for the identification of significant correlations. Parallel to our earlier findings involving comparisons across 95 patients,9 in this study we found evidence of a strong relationship between anxiety and depression over time. The majority of patients (57.7%) showed a significant correlation across monthly assessments between the BDI and SEQ, and the average value of the correlation for all subjects was .68. In the examination of the relationships between dysphoria (depression and anxiety) and positive and negative symptoms, we initially calculated four correlations for each patient. These were the correlations across time of scores on the BDI and SEQ with total scores on the SAPS and SANS. The percentage of patients whose data showed significant (P < .025) correlations between each pair of symptoms is presented in the top portion of Table 2. Contrasts using a test of differences in proportions showed that there was a greater proportion of significant correlations with the SAPS than with the SANS for both the BDI and SEQ (x2 (1) = 8.89, P < .Ol, x2 (1) = 4.29, P < .05, respectively). We calculated the number of patients for whom there was a significant correlation between the BDI or SEQ and each of the SAPS Table 2. Percentage of Significant Correlations of Dysphoria With Positive and Negative Symptoms (n = 52) Symptom
Measure
Depression
(BDI)
Anxiety (SEQ)
25%
SAPS total
36.5%
SANS total
11.5%
Reality distortion
29.2%
25%
Disorganization
19.2%
11.5%
Psychomotor poverty
13.5%
5.7%
9.6%
and SANS. This provides a more general index of the differential relationship between dysphoria and positive and negative symptoms. The figure was 48.1% for the SAPS and 17.3% for the SANS; the two proportions differed significantly (x2 (1) = 11.18, P < .OOl). The differential rate of association between measures of dysphoria and positive and negative symptoms could result from there being less variation over time in negative symptoms than in positive symptoms. If more patients show restrictive range on negative symptoms, then this would mean that the lower proportion of significant correlations with the SANS essentially reflects a statistical artifact. Further examination of our data show that this is not the case. We calculated the percentage of patients who over time showed a range of scores on the SAPS and SANS equal to or greater than 10% of the maximum possible range. In actual fact, a larger number of patients met this criterion for the SANS (47 patients) than for the SAPS (23 patients; see also Malla et a1.22).Furthermore, when we restricted our examination of correlates for each of the SAPS and SANS to those who met this range criterion, there was still a significantly higher proportion of significant correlations of the BDI and SEQ with the SAPS than with the SANS (47.8% v 12.7% and 39% v 10.6%, respectively). As indicated earlier, recent research suggests that the symptoms assessed by the SAPS and SANS actually reflect three underlying dimensions of symptomatology in schizophrenia, i.e., reality distortion, disorganization, and psychomotor poverty. Following the guidelines from previous research and factor analysis of symptoms from this sample, we divided the items to provide an index of each of these three syndromes. (Information regarding the items used for each of the composite scores can be obtained by writing the authors.) We then calculated the percentage of significant correlations for the BDI and SEQ with each of the syndromes; the results are presented in the lower part of Table 2. It can be seen that the highest percentage of significant correlations was found for the reality distortion syndrome, followed by the disorganization syndrome, and the lowest percentage occurred for the psychomotor pov-
DYSPHORIA
AND SYMPTOMATOLOGY
IN SCHIZOPHRENIA
erty syndrome. When proportions of significant correlations are contrasted, only the difference between reality distortion and psychomotor poverty is significant for the SEQ (x2 (1) = 7.23, P < .Ol). For the BDI, this difference closely approaches significance at the .05 level (x’ (1) = 3.71). It should be noted that the percentage of significant positive correlations that would be expected to occur by chance in each cell of Table 2 is 2.5%. In almost all cells (with the possible exception of the relationship between the SEQ and psychomotor poverty), the percentage of significant correlations observed is at least several magnitudes greater than chance expectation. We contrasted the number of significant dysphoriaisymptom correlations that were found for patient groupings defined by gender, as well as median splits on such variables as age, number of previous psychiatric admissions, and chlorpromazine equivalence dosage of neuroleptic medication. The results provided no evidence of any of these variables being related to the number of significant correlations. There was no evidence that patients who were receiving anticholinergic medication showed a different proportion of significant correlations than those who were not receiving anticholinergics. DISCUSSION
It has been argued that there is considerable overlap between negative symptoms and depression.‘,’ As we have suggested elsewhere,9 the data that have been presented in favor of this argument are characterized either by there being no appropriate comparison group,’ or by observational ratings of depression and negative symptoms being performed by the same raters.’ On an observational level, many of the behaviors attributed to negative symptoms and depression, such as slowness, withdrawal, decrease in sexual drive, etc., are indistinguishable. Our finding of a longitudinal relationship between negative symptoms and depression for a very modest proportion of patients is consistent with two previous reports of cross-sectional data using self-report measures of depression.b,y The contrast between studies suggesting a strong
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relationship between depression and negative symptoms and those suggesting a very modest or no relationship cannot be explained entirely by the use of rating scale versus self-report indices of depression. There are now several reports using observer ratings of both depression and negative symptoms that also conclude that there is little if any relationship between the two.“,3.8.‘” The general weight of evidence is therefore suggests that depression and negative symptoms are largely independent. On the other hand, our longitudinal data add further support to the argument that dysphoria (including both d epression and anxiety) is more strongly related to positive symptoms. This is consistent with previous cross-sectional studies using self-report measures of dysphoria.b,y It should also be noted that Hirsch et al.,“” in reviewing evidence from several studies using both rating scales and self-report measures, suggest that there is evidence of a more reliable relationship of depression with psychotic or positive symptoms rather than with negative symptoms. Such findings are consistent with the suggestion by several investigators that dysphoric mood is often associated with an increase in the likelihood of positive psychotic features of schizophrenia.‘4-‘6 In individuals vulnerable to schizophrenia, dysphoria may serve as a mediator in the development of positive symptoms in response to psychosocial stressors 27.18 Our results suggest that the relationship between dysphoria and reality distortion (hallucinations and delusions) is the most robust. It is tempting to speculate that this closer relationship between dysphoria and reality distortion may have pathophysiologic significance. The reality distortion syndrome is reported to be related to dysfunction in the left medial temporal lobe’” and is thus related closely to the rest of the limbic system, which is recognized as playing an important role in emotional responses. ACKNOWLEDGMENT Assistance was provided by North Nay Psychiatric Hospital. Dr. Peter Williamson and the staff of the active treatment unit of London Psychiatric Hospital, and the case managers of the Community Rehabilitation Program of Victoria Hospital.
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NORMAN AND MALLA
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