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The frequency of associations between positive and negative symptoms and dysphoria in schizophrenia
The Frequency of Associations Between Positive and Negative Symptoms and Dysphoria in Schizophrenia Paul H. Lysaker, Morris D. Bell, Stephen M. Bioty, and Wayne S. Zito Weekly assessments of depression, anxiety, and positive and negative symptoms were performed on 80 subjects with schizophrenia or schizoaffective disorder. Using procedures previously reported in another study, the frequency of significant correlations between the sum of anxiety and depression ratings and positive symptoms was compared with the frequency of significant correlations between the sum of anxiety and depression ratings and negative symptoms. Re-
suits confirm that dysphoria in schizophrenia tends to be more frequently associated with positive versus negative symptoms, regardless of diagnostic subtype or symptom type. This provides further evidence of the independence of negative symptoms from dysphoria and suggests that the level of positive symptoms and level of dysphoria may mutually influence one another. Copyright © 1995by W.B. Saunders Company
A
symptom total than there is between dysphoria and negative symptom total. This study attempts to replicate the statistical procedures reported by Norman and Malla 6 using a different instrument to measure symptoms and a shorter interval between assessments. This study also examines a significantly different sample of subjects, which includes subjects with a diagnosis of schizoaffective disorder. We believe inclusion of subjects with schizoaffective disorder is highly relevant, since the broad range of affective symptoms these subjects have experienced is likely to provide important information about the interrelationship of positive and negative symptoms with depression. A finding that positive symptoms are more frequently correlated with dysphoria than are negative symptoms under these experimental conditions would greatly increase the generalizability of the results reported by Norman and Malla. It would thereby provide stronger support for the theory that negative symptoms and dysphoria represent distinct phenomena in schizophrenia. This study also investigates whether associations observed between dysphoria and symptoms differ according to diagnostic subtypes. For example, might an association between
CONSIDERABLE AMOUNT of research has addressed the concern 1,2 that there is substantial overlap between negative symptoms and depression in schizophrenia. Many of these studies have been in the form of correlational analyses that compare associations between various depressive symptoms and negative and positive symptoms. To date, this line of research has produced contradictory findings. Whereas several studies have found a strong relationship between negative symptoms and depressive symptoms, 3,4 others have found that some depressive symptoms are more strongly associated with positive versus negative symptoms. 5 Explanations for these inconsistencies include rater bias and differing operational definitions of depressive symptoms. Additionally, Norman and Malla 6 have pointed out that these studies have used cross-sectional data, which may lead to incorrect interpretation of the relationship between symptoms of individual patients. To address these problems, Norman and Malla 6 compared the frequency of correlations of self-reported depression and anxiety with positive and negative symptom totals using the Schedule for the Assessment of Negative Symptoms and Schedule for the Assessment of Positive Symptoms for 52 subjects, each with a minimum of 12 symptom interviews conducted at least 1 month apart. They found that the proportion of subjects whose report of either depression or anxiety covaried significantly with positive symptoms was greater than the proportion whose report of depression or anxiety covaried significantly with negative symptoms. They concluded that there is a more consistent relationship between dysphoria and positive
From the Veterans Administration Medical Center, West Haven; and Yale University School of Medicine, West Haven, CT. Supported by the Department of Veterans Affairs Rehabilitation, Research, and Development Service. Address reprint requests to Paul H. Lysaker, Ph.D., Psychology 116-B4, VA Medical Center, West Haven, CT06516. Copyright © 1995 by W.B. Saunders Company 0010-440X/95/3602-0002503.00/0
ComprehensivePsychiatry, Vol. 35, No. 2 (March/April), 1995:pp 113-117
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LYSAKER ET AL
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positive symptoms and dysphoria occur solely in subjects with a diagnosis of the paranoid subtype, or might it be a reflection of schizophrenia in general? This study similarly explores whether significant correlations between dysphoria and symptoms occur more frequently for subjects with certain patterns of positive and negative symptoms. For example, are negative symptoms related to dysphoria only for subjects whose symptomatology could be classified as prominently negative, as opposed to positive or mixed? Such a finding would suggest that this association is not a general feature of the illness, but instead applies only to the negative subtype. '
METHOD
From an initial pool of 150 subjects enrolled in a vocational rehabilitation program, 80 subjects were selected for inclusion solely on the basis of whether they attended at least 12 symptom interviews. Twelve interviews was chosen as a minimum to be consistent with the procedures reported by Norman and Malla. Subjects were recruited from inpatient and outpatient services of the Psychiatry Service of West Haven Veterans Administration Medical Center, and all had a Structured Clinical Interview for DSM-III-R (SCID)-confirmed 7 diagnosis of schizophrenia or schizoaffective disorder. The SCID was conducted by the project director (P.H.L.), a clinical research psychologist. Cases in which there was reasonable doubt about the final diagnosis were resolved through consultation with the Neuropsychiatric Studies unit of West Haven Veterans Administration Medical Center. No subject had a change in medication or housing status in the month preceding entry onto the study. Other exclusion criteria included organic brain syndrome or significant physical handicap. Subject characteristics are listed in Table 1 alongside those reported by Norman and Malla. A chi square analysis comparing the samples in terms of gender and education showed that the two samples significantly differ, with the sample of this study having more men and a higher level of 2 = 18.32 and education (X~I)= 11.41 and P < .001, ×(5) P < .01, respectively). In addition, this sample contains a mix of inpatients and outpatients, has subjects with schizoaffective disorder, and also appears to have subjects with more lifetime psychiatric hospitalizations. All raters were blind to the hypotheses, and symptom ratings were made using the Positive and Negative Syndrome Scale for Schizophrenia (PANSS), 8 a 30-item rating scale completed by clinically trained research staff at the conclusion of chart review and semistructured interview. Positive and negative symptoms were measured using the rationally derived positive symptom total (sum of seven positive items) and negative symptom total (sum of seven negative items). Using the procedure reported by Norman and Malla, who considered measures of anxiety and depression to reflect a larger phenomenon they labeled dysphoric mood, this study additively combined the depression and
Table 1. Background Characteristics of Subjects in This Study and Those Reported by Norman and Malla
Gender Male Female Educational level Incomplete primary Primary complete, but no secondary Incomplete secondary Secondary complete, but no postsecondary Postsecondary (college), but incomplete Postsecondary complete Age (yr) Mean Range No. of psychiatric admissions Mean Range IQ Mean Range Treatment status Inpatient Outpatient Halfway house Ethnicity African-American Latino White
Norman and Malla (N = 55)
This Study (N = 80)
40 (72.7%) 15 (27.3%)
75 (93.7%) 5 (6.2%)
2 (3.6%)
1 (1.3%)
1 (1.8%) 16 (29.8%)
2 (2.5%) 10 (12.5%)
9 (15.7%)
35 (43.8%)
14 (25.4%) 13 (23.7%)
25 (31.3%) 7 (8.8%)
37.8 21-53
42.5 24-66
3 1-9
8 0-39
NR NR
101.6 73-141
0 55 0
12 51 17
NR NR NR
28 3 49
Abbreviation: NR, not reported.
anxiety items from the PANSS general scale for each subject to measure dysphoria. Although they are single global ratings, both the PANSS depression and anxiety items sample a full range of behavior including disturbances of mood, appetite, sleep, and concentration, as well as impaired psychomotor function and relevant somatic complaints. lnterrater reliability was assessed using the intraclass r. Excellent reliabilities were found for the positive and negative total scores (r = .93 and .94, respectively), and good interrater reliabilities were found for the depression and anxiety items (r = .80 and .77). Reliabilities for individual items comprising the positive and negative scale are in the study reported by Bell et al.9 Symptom interviews were conducted at intake, over the next 26 consecutive weeks during the rehabilitation period, and then at a follow-up point 6 months after rehabilitation (see Bell et al. 1° for a description of the rehabilitation program). Using the procedures reported by Norman and Malla, 6 this study examined the two PANSS positive and negative rational scales and three factor-analytically derived PANSS component scores: positive, negative, and cognitive) 1 One
POSITIVE AND NEGATIVE SYMPTOMS AND DYSPHORIA IN SCHIZOPHRENIA
major difference between the empirically derived PANSS scores and the rational scales is that items measuring cognitive impairment are removed from the negative and positive rational scales and placed in their own scale, the cognitive component. The cognitive component of the PANSS has been shown to have concurrent and factorial validity. 12Use of the cognitive component is consistent with a broad body of research suggesting that schizophrenia may be best described along three dimensions, which include a measure of cognitive impairment. 13 Finally, subjects in this study were classified according to predominant symptom typology. Subjects were classified as predominantly positive if their rational positive total was greater than 17 and their negative total was _<17. They were classified as predominantly negative if their rational negative total was greater than 17 and their positive total was < 17. Subjects with scores greater than 17 on both scales were classified as mixed, and subjects with scores less than 17 on either scale were classified as neither. The cutoff score of greater than 17 was chosen a priori to ensure that all subjects classified as prominently negative, positive, or mixed would have at least one severe symptom or a wide range of less severe but clinically significant ratings (five mild, three moderate, or two moderate-severe) from the appropriate scale.
RESULTS First, a Pearson product-moment correlation was calculated between depression and anxiety as rated on the PANSS general scale at intake. The strong relationship revealed by this analysis (r = .56, P < .001) lends support to the rationale for combining these symptom scores to create an index of dysphoria. Next, the dysphoria index was correlated for each subject with positive and negative symptoms using both the rational and factor-analytically derived subscales. A paired t test comparing the means of the correlations showed that correlations between dysphoria and rational positive symptom total (r = .38) were significantly higher than those between dysphoria and rational negative symptom total (r = .20,/(79) = 4.68, P < .0001). To examine the relationship of dysphoria to other forms of symptomatology, we calculated the percentage of subjects whose dysphoria score showed significant (P < .025, one-tailed) correlations with each of the other symptom measures (Table 2). Contrasts using a test of differences in proportions showed that there was a greater proportion of significant correlations between dysphoria and the positive symptom total than between dysphoria and the negative symptom total (X~l) = 8.44, P < .01). An overall difference in proportions was also
115
Table 2. Frequency of Significant Correlations of Dysphoria With Symptom Measures (N = 80) Significant Correlation PANSS Symptom
With Dysphoria
Measure
No.
%
Rational positive total
41
51.3
Rational negative total
23
28.8*
Positive component
42
52.5
Cognitive component Negative component
30 25
37.5 31.3t
*x~l) = 8.44, P < .01. tx~2] = 7.92, P < .02.
detected among factor-analytically derived positive, cognitive, and negative components (×~2) = 7.92, P < .02). Multiple comparisons of the proportions showed that the positive component had a significantly greater number of significant correlations than the negative component (X~2)= 7.77, P < .05). Contrasts of the cognitive component with the positive and negative components showed no significant differences. To examine whether significant dysphoria/ positive symptom correlations occurred more frequently in certain subtypes, a comparison was made according to diagnostic subtype and symptom prevalence (Table 3). These analyses showed no evidence that subjects with SCIDconfirmed diagnoses of schizoaffective disorder, schizophrenia of the paranoid subtype, or schizophrenia of a nonparanoid subtype had differing proportions of significant dysphoria/positive symptom correlations. To examine whether significant dysphoria/positive symptom correlations occurred more often among patients with particular patterns of positive and negative symptoms, a comparison was performed for the Table 3. Frequency of Significant Correlations Between PANSS Positive Total and Dysphoria for Diagnostic Subtypes DSM-III-R Diagnosis Schizoaffective Disorder (n = 24)
Significant correlation Nonsignificant correlation
Schizophrenia ParanoidType (n = 32)
Schizophrenia Nonparanoid Type (n = 24)*
No.
%
No.
%
No.
%
15
62.5
16
50.0
10
41.7t
9
37.5
16
50.0
14
58.3
*SCID-confirmed: undifferentiated type, n = 20; disorganized type, n = 2; residual type, n = 2. tx~2i = 2.12, P = NS.
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LYSAKER ET AL
numbers of significant correlations between subjects whose symptoms were predominantly of the positive, negative, mixed, or neither type (Table 4). This analysis showed no evidence that the proportions of significant correlations differed between groups. DISCUSSION
The results suggest that dysphoria in schizophrenia is more frequently associated with positive rather than negative symptoms regardless of diagnostic subtype or predominant symptom type. The findings of this study parallel those reported by Norman and Malla 6 despite differing methods of assessment and subject samples with significantly different background characteristics. Results of this study and those of Norman and Malla suggest that although negative symptoms and dysphoria may overlap conceptually (e.g., both may involve loss of interest and apathy), their fluctuations over time are only minimally related. In fact, mean correlations for this sample indicated that negative symptoms accounted for an average of only 4% of the variance in dysphoria over time, whereas positive symptoms accounted for an average of 14% of the variance. Positive symptoms covaried with dysphoria for more than half our sample. This raises several intriguing issues regarding the etiology and course of psychopathology in schizophrenia. For example, the factor analyses of the PANSS discussed earlier found five independent factors including positive symptoms, negative symptoms, and symptoms of emotional discomfort. Given the fact that these factors were orthogonally constructed at baseline, why does dysphoria covary with positive symptoms and dysphoria over time? Although the correlational nature of these data precludes any definiTable 4. Frequency of Significant Correlations Between PANSS Positive Total and Dysphoria for Symptom Subtypes Predominant Symptom Type
Positive
Negative
(n = 31)
(n = 17)
Neither (n = 18)
Mixed (n = 14)
No.
%
No.
%
No.
%
No.
%
17
54.8
9
52.9
7
38.9
8
57.1"
14
45.2
8
47.1
11
61.1
6
42.9
Significant
correlation Nonsignificant correlation
*X(3)2 = 1.48, P = NS.
tive statements regarding causality, we would like to offer some hypotheses about these issues for further investigation. First, the covariance observed between positive symptoms and dysphoria suggests that positive symptoms may be closely related to emotional states: exacerbations in positive symptoms may increase feelings of helplessness and distress, and increased dysphoria could exacerbate hallucinations or delusions. We hypothesize that for the subjects in this study, stress at home or on the job led to increased emotional upset and dysphoria. This increased dysphoria exacerbated positive symptoms. Increased positive symptoms, in turn, were distressing and led to heightened dysphoria, which may have once again increased positive symptoms. This hypothesis is consistent with psychosocial-biological interactive models of psychopathology (e.g., Ciompi14), which posit that severely distressing life events contribute to the first break of psychosis and to a prolonged course of illness in vulnerable individuals. It is also consistent with neurological models that link positive symptoms with cortical overarousal or other states potentially exacerbated by significant emotional distress. 15 A second question raised by the results of this study is why did not a similarly covarying relationship occur between negative symptoms and dysphoria? Why would exacerbations in negative symptoms not lead to heightened dysphoria, or increased dysphoria not lead to heightened negative symptoms? One hypothesis is that negative symptoms, in contrast to positive symptoms, represent a deficit state 16 in which patients have a significantly reduced capacity for internal experience. Therefore, they may not experience heightened sadness, hopelessness, or uneasiness with fluctuations in negative symptoms. This hypothesis is consistent with neurological models that suggest negative symptoms correspond to a downregulation of the limbic system. 15 Support for this hypothesis can be found in studies demonstrating that positive symptoms are more responsive to stressors than negative symptoms, 17,18and in reports that subjects with prominent negative symptoms are significantly more egocentrically withdrawn but less anguished and less interpersonally insecure
POSITIVE AND NEGATIVE SYMPTOMS AND DYSPHORIA IN SCHIZOPHRENIA
than subjects without prominent negative symptoms. 19 Finally, these results suggest that future research should explore whether interventions that reduce dysphoria also reduce positive symptoms. In particular, it would be important to learn whether positive symptoms and dysphoria covary in a similar manner in long-term treatments that include medications and psychosocial supports. Such research would have important implications for treatment and for understanding interrelationships between various features of psychopathology in schizophrenia. There are limitations to this study. Subjects were assessed while they were involved in rehabilitation. Therefore, it may be that the covariance observed between positive symptoms and dysphoria reflects a treatment effect rather than a naturally occurring interdependence (i.e., both were similarly affected by rehabilitation). Additionally, both the current study and that re-
117
ported by Norman and Malla used global measures of anxiety and depression (Beck Depression Inventory and Self-Evaluation Questionnaire totals and PANSS depression and anxiety items). It may be that research separately examining the individual features of depression and anxiety will detect divergent patterns of relationships between the individual characteristics of anxiety and depression and negative and positive symptoms. Finally, there were several similarities between the sample studied in this experiment and the sample reported by Norman and Malla. In particular, both contained predominantly men in a relatively stable phase of illness who were generally in their mid-thirties or older. Future research may seek to extend this line of study using samples with more women, as well as more subjects who have recently experienced their first break or are in an acute phase of illness.
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. Lindenmayer JP, Kay SR. Depression, affect and negative symptoms in schizophrenia. Br J Psychiatry 1989; 155:108-114. 4. Kulhara P, Avasthi A, Chadda R, Chandiramani K, Mattoo SK, Joseph S. Negative symptoms and depression in schizophrenia. Br J Psychiatry 1989;154:207-211. 5. Barnes TR, Curson DA, Liddle PF, Patel M. The nature and prevalence of depression in chronic schizophrenic inpatients. Br J Psychiatry 1989;154:486-491. 6. Norman RMG, Malla AK. Correlations over time between dysphoric mood and symptomatology in schizophrenia. Compr Psychiatry 1994;35:34-38. 7. Spitzer RL, Williams JB, Gibbon M, First MB. Structured Clinical Interview for DSM-III-R. New York, NY: Biometrics Research Department, 1989. 8. Kay SR, Fiszbein A, Opler LA. The Positive and Negative Syndrome Scale (PANSS) for Schizophrenia. Schizophr Bull 1987;13:261-276. 9. Bell MD, Milstein RM, Goulet JB, Lysaker PH, Cicchetti D. The Positive and Negative Syndrome Scale and Brief Psychiatric Rating Scale: reliability and predictive validity. J Nerv Ment Dis 1992;180:723-728. 10. Bell MD, Milstein RM, Lysaker PH. Pay and partici-
pation in work activity: clinical benefits for clients with schizophrenia. Psychosocial Rehab J 1993;17:173-177. 11. Bell MD, Lysaker PH, Milstein RM, Goulet JG. Five factor model of schizophrenia. Psychiatry Res 1994;52:295303. 12. Mortimer AM, Lund CE, McKenna PJ. The positive: negative dichotomy in schizophrenia. Br J Psychiatry 1990; 157:41-49. 13. Bell MD, Lysaker PH, Milstein RM, Goulet JG. Cognitive component of schizophrenia: factorial and concurrent validity. Psychiatry Res 1994;54:51-58. 14. Ciompi L. Affect logic: an integrative model of the psyche and its relation to schizophrenia. Br J Psychiatry 1994;164(23 suppl):51-55. 15. Andreascn NC. Neural mechanisms of negative symptoms. Br J Psychiatry 1989;155 (7 Suppl):93-98. 16. Buchanan RW, Carpenter WT. Domains of psychopathology: an approach to the reduction of heterogeneity in schizophrenia. J Nerv Ment Dis 1994;182:193-204. 17. Schwartz CC, Meyers JK. Life events and schizophrenia: II. Impact of life events on symptoms configuration. Arch Gen Psychiatry 1977;34:1242-1245. 18. Docherty NM, Evans IM, Sledge WH, Seibyl JP, Krystal JH. Affective reactivity of language in schizophrenia. J Nerv Ment Dis 1994;182:98-102. 19. Bell MD, Lysaker PH, Milstein RM. Object relations deficits in subtypes of schizophrenia. J Clin Psychol 1992;48: 433-445.
suits confirm that dysphoria in schizophrenia tends to be more frequently associated with positive versus negative symptoms, regardless of diagnostic subtype or symptom type. This provides further evidence of the independence of negative symptoms from dysphoria and suggests that the level of positive symptoms and level of dysphoria may mutually influence one another. Copyright © 1995by W.B. Saunders Company
A
symptom total than there is between dysphoria and negative symptom total. This study attempts to replicate the statistical procedures reported by Norman and Malla 6 using a different instrument to measure symptoms and a shorter interval between assessments. This study also examines a significantly different sample of subjects, which includes subjects with a diagnosis of schizoaffective disorder. We believe inclusion of subjects with schizoaffective disorder is highly relevant, since the broad range of affective symptoms these subjects have experienced is likely to provide important information about the interrelationship of positive and negative symptoms with depression. A finding that positive symptoms are more frequently correlated with dysphoria than are negative symptoms under these experimental conditions would greatly increase the generalizability of the results reported by Norman and Malla. It would thereby provide stronger support for the theory that negative symptoms and dysphoria represent distinct phenomena in schizophrenia. This study also investigates whether associations observed between dysphoria and symptoms differ according to diagnostic subtypes. For example, might an association between
CONSIDERABLE AMOUNT of research has addressed the concern 1,2 that there is substantial overlap between negative symptoms and depression in schizophrenia. Many of these studies have been in the form of correlational analyses that compare associations between various depressive symptoms and negative and positive symptoms. To date, this line of research has produced contradictory findings. Whereas several studies have found a strong relationship between negative symptoms and depressive symptoms, 3,4 others have found that some depressive symptoms are more strongly associated with positive versus negative symptoms. 5 Explanations for these inconsistencies include rater bias and differing operational definitions of depressive symptoms. Additionally, Norman and Malla 6 have pointed out that these studies have used cross-sectional data, which may lead to incorrect interpretation of the relationship between symptoms of individual patients. To address these problems, Norman and Malla 6 compared the frequency of correlations of self-reported depression and anxiety with positive and negative symptom totals using the Schedule for the Assessment of Negative Symptoms and Schedule for the Assessment of Positive Symptoms for 52 subjects, each with a minimum of 12 symptom interviews conducted at least 1 month apart. They found that the proportion of subjects whose report of either depression or anxiety covaried significantly with positive symptoms was greater than the proportion whose report of depression or anxiety covaried significantly with negative symptoms. They concluded that there is a more consistent relationship between dysphoria and positive
From the Veterans Administration Medical Center, West Haven; and Yale University School of Medicine, West Haven, CT. Supported by the Department of Veterans Affairs Rehabilitation, Research, and Development Service. Address reprint requests to Paul H. Lysaker, Ph.D., Psychology 116-B4, VA Medical Center, West Haven, CT06516. Copyright © 1995 by W.B. Saunders Company 0010-440X/95/3602-0002503.00/0
ComprehensivePsychiatry, Vol. 35, No. 2 (March/April), 1995:pp 113-117
113
LYSAKER ET AL
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positive symptoms and dysphoria occur solely in subjects with a diagnosis of the paranoid subtype, or might it be a reflection of schizophrenia in general? This study similarly explores whether significant correlations between dysphoria and symptoms occur more frequently for subjects with certain patterns of positive and negative symptoms. For example, are negative symptoms related to dysphoria only for subjects whose symptomatology could be classified as prominently negative, as opposed to positive or mixed? Such a finding would suggest that this association is not a general feature of the illness, but instead applies only to the negative subtype. '
METHOD
From an initial pool of 150 subjects enrolled in a vocational rehabilitation program, 80 subjects were selected for inclusion solely on the basis of whether they attended at least 12 symptom interviews. Twelve interviews was chosen as a minimum to be consistent with the procedures reported by Norman and Malla. Subjects were recruited from inpatient and outpatient services of the Psychiatry Service of West Haven Veterans Administration Medical Center, and all had a Structured Clinical Interview for DSM-III-R (SCID)-confirmed 7 diagnosis of schizophrenia or schizoaffective disorder. The SCID was conducted by the project director (P.H.L.), a clinical research psychologist. Cases in which there was reasonable doubt about the final diagnosis were resolved through consultation with the Neuropsychiatric Studies unit of West Haven Veterans Administration Medical Center. No subject had a change in medication or housing status in the month preceding entry onto the study. Other exclusion criteria included organic brain syndrome or significant physical handicap. Subject characteristics are listed in Table 1 alongside those reported by Norman and Malla. A chi square analysis comparing the samples in terms of gender and education showed that the two samples significantly differ, with the sample of this study having more men and a higher level of 2 = 18.32 and education (X~I)= 11.41 and P < .001, ×(5) P < .01, respectively). In addition, this sample contains a mix of inpatients and outpatients, has subjects with schizoaffective disorder, and also appears to have subjects with more lifetime psychiatric hospitalizations. All raters were blind to the hypotheses, and symptom ratings were made using the Positive and Negative Syndrome Scale for Schizophrenia (PANSS), 8 a 30-item rating scale completed by clinically trained research staff at the conclusion of chart review and semistructured interview. Positive and negative symptoms were measured using the rationally derived positive symptom total (sum of seven positive items) and negative symptom total (sum of seven negative items). Using the procedure reported by Norman and Malla, who considered measures of anxiety and depression to reflect a larger phenomenon they labeled dysphoric mood, this study additively combined the depression and
Table 1. Background Characteristics of Subjects in This Study and Those Reported by Norman and Malla
Gender Male Female Educational level Incomplete primary Primary complete, but no secondary Incomplete secondary Secondary complete, but no postsecondary Postsecondary (college), but incomplete Postsecondary complete Age (yr) Mean Range No. of psychiatric admissions Mean Range IQ Mean Range Treatment status Inpatient Outpatient Halfway house Ethnicity African-American Latino White
Norman and Malla (N = 55)
This Study (N = 80)
40 (72.7%) 15 (27.3%)
75 (93.7%) 5 (6.2%)
2 (3.6%)
1 (1.3%)
1 (1.8%) 16 (29.8%)
2 (2.5%) 10 (12.5%)
9 (15.7%)
35 (43.8%)
14 (25.4%) 13 (23.7%)
25 (31.3%) 7 (8.8%)
37.8 21-53
42.5 24-66
3 1-9
8 0-39
NR NR
101.6 73-141
0 55 0
12 51 17
NR NR NR
28 3 49
Abbreviation: NR, not reported.
anxiety items from the PANSS general scale for each subject to measure dysphoria. Although they are single global ratings, both the PANSS depression and anxiety items sample a full range of behavior including disturbances of mood, appetite, sleep, and concentration, as well as impaired psychomotor function and relevant somatic complaints. lnterrater reliability was assessed using the intraclass r. Excellent reliabilities were found for the positive and negative total scores (r = .93 and .94, respectively), and good interrater reliabilities were found for the depression and anxiety items (r = .80 and .77). Reliabilities for individual items comprising the positive and negative scale are in the study reported by Bell et al.9 Symptom interviews were conducted at intake, over the next 26 consecutive weeks during the rehabilitation period, and then at a follow-up point 6 months after rehabilitation (see Bell et al. 1° for a description of the rehabilitation program). Using the procedures reported by Norman and Malla, 6 this study examined the two PANSS positive and negative rational scales and three factor-analytically derived PANSS component scores: positive, negative, and cognitive) 1 One
POSITIVE AND NEGATIVE SYMPTOMS AND DYSPHORIA IN SCHIZOPHRENIA
major difference between the empirically derived PANSS scores and the rational scales is that items measuring cognitive impairment are removed from the negative and positive rational scales and placed in their own scale, the cognitive component. The cognitive component of the PANSS has been shown to have concurrent and factorial validity. 12Use of the cognitive component is consistent with a broad body of research suggesting that schizophrenia may be best described along three dimensions, which include a measure of cognitive impairment. 13 Finally, subjects in this study were classified according to predominant symptom typology. Subjects were classified as predominantly positive if their rational positive total was greater than 17 and their negative total was _<17. They were classified as predominantly negative if their rational negative total was greater than 17 and their positive total was < 17. Subjects with scores greater than 17 on both scales were classified as mixed, and subjects with scores less than 17 on either scale were classified as neither. The cutoff score of greater than 17 was chosen a priori to ensure that all subjects classified as prominently negative, positive, or mixed would have at least one severe symptom or a wide range of less severe but clinically significant ratings (five mild, three moderate, or two moderate-severe) from the appropriate scale.
RESULTS First, a Pearson product-moment correlation was calculated between depression and anxiety as rated on the PANSS general scale at intake. The strong relationship revealed by this analysis (r = .56, P < .001) lends support to the rationale for combining these symptom scores to create an index of dysphoria. Next, the dysphoria index was correlated for each subject with positive and negative symptoms using both the rational and factor-analytically derived subscales. A paired t test comparing the means of the correlations showed that correlations between dysphoria and rational positive symptom total (r = .38) were significantly higher than those between dysphoria and rational negative symptom total (r = .20,/(79) = 4.68, P < .0001). To examine the relationship of dysphoria to other forms of symptomatology, we calculated the percentage of subjects whose dysphoria score showed significant (P < .025, one-tailed) correlations with each of the other symptom measures (Table 2). Contrasts using a test of differences in proportions showed that there was a greater proportion of significant correlations between dysphoria and the positive symptom total than between dysphoria and the negative symptom total (X~l) = 8.44, P < .01). An overall difference in proportions was also
115
Table 2. Frequency of Significant Correlations of Dysphoria With Symptom Measures (N = 80) Significant Correlation PANSS Symptom
With Dysphoria
Measure
No.
%
Rational positive total
41
51.3
Rational negative total
23
28.8*
Positive component
42
52.5
Cognitive component Negative component
30 25
37.5 31.3t
*x~l) = 8.44, P < .01. tx~2] = 7.92, P < .02.
detected among factor-analytically derived positive, cognitive, and negative components (×~2) = 7.92, P < .02). Multiple comparisons of the proportions showed that the positive component had a significantly greater number of significant correlations than the negative component (X~2)= 7.77, P < .05). Contrasts of the cognitive component with the positive and negative components showed no significant differences. To examine whether significant dysphoria/ positive symptom correlations occurred more frequently in certain subtypes, a comparison was made according to diagnostic subtype and symptom prevalence (Table 3). These analyses showed no evidence that subjects with SCIDconfirmed diagnoses of schizoaffective disorder, schizophrenia of the paranoid subtype, or schizophrenia of a nonparanoid subtype had differing proportions of significant dysphoria/positive symptom correlations. To examine whether significant dysphoria/positive symptom correlations occurred more often among patients with particular patterns of positive and negative symptoms, a comparison was performed for the Table 3. Frequency of Significant Correlations Between PANSS Positive Total and Dysphoria for Diagnostic Subtypes DSM-III-R Diagnosis Schizoaffective Disorder (n = 24)
Significant correlation Nonsignificant correlation
Schizophrenia ParanoidType (n = 32)
Schizophrenia Nonparanoid Type (n = 24)*
No.
%
No.
%
No.
%
15
62.5
16
50.0
10
41.7t
9
37.5
16
50.0
14
58.3
*SCID-confirmed: undifferentiated type, n = 20; disorganized type, n = 2; residual type, n = 2. tx~2i = 2.12, P = NS.
116
LYSAKER ET AL
numbers of significant correlations between subjects whose symptoms were predominantly of the positive, negative, mixed, or neither type (Table 4). This analysis showed no evidence that the proportions of significant correlations differed between groups. DISCUSSION
The results suggest that dysphoria in schizophrenia is more frequently associated with positive rather than negative symptoms regardless of diagnostic subtype or predominant symptom type. The findings of this study parallel those reported by Norman and Malla 6 despite differing methods of assessment and subject samples with significantly different background characteristics. Results of this study and those of Norman and Malla suggest that although negative symptoms and dysphoria may overlap conceptually (e.g., both may involve loss of interest and apathy), their fluctuations over time are only minimally related. In fact, mean correlations for this sample indicated that negative symptoms accounted for an average of only 4% of the variance in dysphoria over time, whereas positive symptoms accounted for an average of 14% of the variance. Positive symptoms covaried with dysphoria for more than half our sample. This raises several intriguing issues regarding the etiology and course of psychopathology in schizophrenia. For example, the factor analyses of the PANSS discussed earlier found five independent factors including positive symptoms, negative symptoms, and symptoms of emotional discomfort. Given the fact that these factors were orthogonally constructed at baseline, why does dysphoria covary with positive symptoms and dysphoria over time? Although the correlational nature of these data precludes any definiTable 4. Frequency of Significant Correlations Between PANSS Positive Total and Dysphoria for Symptom Subtypes Predominant Symptom Type
Positive
Negative
(n = 31)
(n = 17)
Neither (n = 18)
Mixed (n = 14)
No.
%
No.
%
No.
%
No.
%
17
54.8
9
52.9
7
38.9
8
57.1"
14
45.2
8
47.1
11
61.1
6
42.9
Significant
correlation Nonsignificant correlation
*X(3)2 = 1.48, P = NS.
tive statements regarding causality, we would like to offer some hypotheses about these issues for further investigation. First, the covariance observed between positive symptoms and dysphoria suggests that positive symptoms may be closely related to emotional states: exacerbations in positive symptoms may increase feelings of helplessness and distress, and increased dysphoria could exacerbate hallucinations or delusions. We hypothesize that for the subjects in this study, stress at home or on the job led to increased emotional upset and dysphoria. This increased dysphoria exacerbated positive symptoms. Increased positive symptoms, in turn, were distressing and led to heightened dysphoria, which may have once again increased positive symptoms. This hypothesis is consistent with psychosocial-biological interactive models of psychopathology (e.g., Ciompi14), which posit that severely distressing life events contribute to the first break of psychosis and to a prolonged course of illness in vulnerable individuals. It is also consistent with neurological models that link positive symptoms with cortical overarousal or other states potentially exacerbated by significant emotional distress. 15 A second question raised by the results of this study is why did not a similarly covarying relationship occur between negative symptoms and dysphoria? Why would exacerbations in negative symptoms not lead to heightened dysphoria, or increased dysphoria not lead to heightened negative symptoms? One hypothesis is that negative symptoms, in contrast to positive symptoms, represent a deficit state 16 in which patients have a significantly reduced capacity for internal experience. Therefore, they may not experience heightened sadness, hopelessness, or uneasiness with fluctuations in negative symptoms. This hypothesis is consistent with neurological models that suggest negative symptoms correspond to a downregulation of the limbic system. 15 Support for this hypothesis can be found in studies demonstrating that positive symptoms are more responsive to stressors than negative symptoms, 17,18and in reports that subjects with prominent negative symptoms are significantly more egocentrically withdrawn but less anguished and less interpersonally insecure
POSITIVE AND NEGATIVE SYMPTOMS AND DYSPHORIA IN SCHIZOPHRENIA
than subjects without prominent negative symptoms. 19 Finally, these results suggest that future research should explore whether interventions that reduce dysphoria also reduce positive symptoms. In particular, it would be important to learn whether positive symptoms and dysphoria covary in a similar manner in long-term treatments that include medications and psychosocial supports. Such research would have important implications for treatment and for understanding interrelationships between various features of psychopathology in schizophrenia. There are limitations to this study. Subjects were assessed while they were involved in rehabilitation. Therefore, it may be that the covariance observed between positive symptoms and dysphoria reflects a treatment effect rather than a naturally occurring interdependence (i.e., both were similarly affected by rehabilitation). Additionally, both the current study and that re-
117
ported by Norman and Malla used global measures of anxiety and depression (Beck Depression Inventory and Self-Evaluation Questionnaire totals and PANSS depression and anxiety items). It may be that research separately examining the individual features of depression and anxiety will detect divergent patterns of relationships between the individual characteristics of anxiety and depression and negative and positive symptoms. Finally, there were several similarities between the sample studied in this experiment and the sample reported by Norman and Malla. In particular, both contained predominantly men in a relatively stable phase of illness who were generally in their mid-thirties or older. Future research may seek to extend this line of study using samples with more women, as well as more subjects who have recently experienced their first break or are in an acute phase of illness.
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