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Aims: The aim of the present study was to develop a subscale of the Positive and Negative Syndrome Scale (PANSS) that would be brief and sensitive to changes in the clinical features of schizophrenia (i.e. the Brief PANSS, or bPANSS).
Methods: The PANSS before and after treatment, and the Clinical Global Impression–Change (CGI-C) was rated for 714 schizophrenia patients. Of these, Clinical Global Impression–Severity (CGI-S) was also evaluated in 30 of these patients. The bPANSS items were extracted from full PANSS items based on the following aims: (i) to develop a brief scale; (ii) to develop a scale sensitive to changes resulting from antipsychotic treatment; and (iii) to reflect the broad spectrum of schizophrenia symptoms.
Results: The following six items were extracted to serve as the bPANSS: delusion, suspiciousness, emotional withdrawal, passive/apathetic social withdrawal, tension, and unusual thought content. The coefficients of correlation between the bPANSS and full PANSS before and after treatment were 0.86 and 0.92, respectively (both P < 0.001). The coefficient of correlation between the degrees of change in the scores for the bPANSS and the full PANSS was 0.93 (P < 0.001), and that between delta bPANSS and CGI-C was 0.73 (P < 0.001).
Conclusions: bPANSS is able to capture the overall clinical features of schizophrenia within a short assessment period.
THE POSITIVE AND Negative Syndrome Scale (PANSS) was developed by Kay et al. for comprehensive assessment of the psychopathology of schizophrenia,1 and is one of the most widely used scales for schizophrenia in both psychopharmacological studies and clinical trials. This scale consists of a total of 30 items including seven positive syndrome items, seven negative syndrome items, and 16 comprehensive pathological items, and the severity of each item is rated on a scale from 1 (none) to 7 (most severe). It takes at least 30–40 min to assess the overall schizophrenic symptoms using the PANSS.2
The PANSS is thus an informative rating instrument for capturing the overall psychopathology of patients with schizophrenia. For repeated evaluation, however, it may be too burdensome for both patients and clinicians. In fact, among the 30 items of the PANSS, there are several symptomatic items that do not change even after pharmacological treatment, considering the natural history of schizophrenia. The aim of the present study was therefore to develop a brief version of the PANSS (bPANSS) to complement the full PANSS.
More specifically, in the present study, we tried to extract the least possible number of items from the original PANSS as long as, first, they retained sufficient internal consistency and reliability while reflecting the three domains of the original PANSS; second, they correlated with the overall severity of schizophrenia; and third, they were sensitive to changes in overall severity. We expected that such a scale would be useful and meaningful for the follow up of patients with schizophrenia in routine clinical practice. To our knowledge this study represents the first attempt to extract the core items from the total 30 items of the PANSS.
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The bPANSS, consisting of six items selected from the 30 items of the full PANSS, showed a high correlation with the full PANSS score, being 0.86 at study entry and 0.92 at the end of treatment. Also, the correlation between delta bPANSS and delta total PANSS was 0.93 (P < 0.001), while that between delta bPANSS and CGI-C was 0.73 (P < 0.001). Furthermore, the correlation between bPANSS and CGI-S was 0.64 at study entry and 0.84 at the end of treatment (both P < 0.001). Considering that it takes a short time to complete the six items, it is believed that the requirements of the bPANSS, which is sensitive to changes in psychotic manifestations and also reflects the profile of schizophrenia to a certain extent, have been satisfied.
Attempts to select several items from among the existing clinical rating scales for certain purposes have been reported for a number of scales. For example, Montgomery and Asberg developed the Montgomery and Asberg Depression Rating Scale,6 which is a representative rating scale for depression consisting of 10 items selected from the Comprehensive Psychopathologic Rating Scale (CPRS), which contains 67 items in all: 40 items for subjective psychopathological symptoms, 25 items for objective psychopathological symptoms, and two items for global rating and assumed reliability.7 For schizophrenia they also selected 12 items that were the most sensitive to changes resulting from treatment, and they subsequently proposed an acute schizophrenia rating scale (brief CPRS) that was more sensitive to therapeutic response than the Brief Psychiatric Rating Scale.8
The six items in the bPANSS and the 12 items in the brief CPRS are shown in Table 5. Ten of the 12 items are related to subjective pathological symptoms in the brief CPRS. This appears to be because the items that respond readily to treatment, such as hallucination and delusion, tend to be measured mainly as subjective pathological symptoms, and the balance of the number of items representing subjective pathological symptoms and objective pathological symptoms is not taken into consideration. In contrast, the items in the bPANSS have been selected from the three psychopathology domains of the original PANSS in a balanced manner. Considering that the correlations of the two selected items within the individual three domains are relatively high (r = 0.517–0.685), it may be possible to simply select three items instead of six.
Table 5. Brief PANSS vs brief CPRS
|Brief PANSS||Brief CPRS|
|Positive Syndrome Scale||Subjective items|
|P1. Delusion||1. Sadness|
|P6. Suspiciousness||5. Inability to feel|
| ||6. Pessimistic thoughts|
|Negative syndrome scale||28. Depersonalization|
|N2. Emotional withdrawal||29. Feeling controlled|
|N4. Passive/apathetic social withdrawal||30. Disrupted thoughts|
| ||31. Ideas of persecution|
|General Pathological Syndrome Scale||33. Delusional mood|
|G4. Tension||36. Other delusions|
|G9. Unusual thought content||37. Commenting voices|
| ||Objective items|
| ||45. Lack of appropriate emotion|
| ||50. Perplexity|
Andreasen et al. extracted eight of the 30 items of the whole PANSS in order to define remission from schizophrenia.9 A total of three items, delusion (P1), passive/apathetic social withdrawal (N4), and unusual thought (G9), overlapped with those currently selected for the bPANSS. These three items are considered to be essentially important for evaluating both remission from schizophrenia and the response to antipsychotic drugs.
Possible limitations of the present study may include the following. First, most of the study subjects were patients enrolled in two multi-center active-drug-controlled clinical trials of a new atypical antipsychotic drug, for whom CGI-S was not evaluated. In other words, we placed more emphasis on the bPANSS to reflect longitudinal changes in psychopathology, rather than reflecting the cross-sectional severity of schizophrenia. Second, all the subjects were receiving active treatment, and therefore changes due to treatment were unable to be differentiated from those due to the natural course of the disorder.
In contrast, the strengths of the bPANSS may be summarized as follows. First, it is brief and therefore exceedingly less burdensome for both patients and clinicians than the full PANSS. Second, it still covers the three broad domains of psychopathology represented by the original scale in a balanced manner. Third, it has high internal consistency reliability. Fourth, the bPANSS shows satisfactory concurrent validity with the full PANSS and the CGI-S for any of the schizophrenia subtypes. Fifth, the bPANSS is sensitive to changes resulting from treatment.
We therefore conclude that the bPANSS is a useful rating instrument that is easy to administer within a short time and is sensitive to changes in the overall clinical features of schizophrenia. One recommended practical application of the scales would be to administer the full PANSS at baseline and then at extended intervals to gain a comprehensive picture of the psychopathology, while in the meantime repeatedly monitoring the changes in the patients using the bPANSS.