Pakistani Woman with Delusional Thought Processes

VOL. 13, NO. 2,1967 The Positive and Negative Syndrome Scale (PANSS) for Schizophrenia

by Stanley R. Kay, Abraham Flszbeln, and Lewis A. QpJer

Abstract

The variable results of positive- negative research with schizo- phrenics underscore the importance of well-characterized, standardized measurement techniques. We report on the development and initial standardization of the Positive and Negative Syndrome Scale (PANSS) for typological and dimensional as- sessment. Based on two established psychiatric rating systems, the 30- item PANSS was conceived as an operationalized, drug-sensitive in- strument that provides balanced representation of positive and nega- tive symptoms and gauges their re- lationship to one another and to global psychopathology. It thus constitutes four scales measuring positive and negative syndromes, their differential, and general sever- ity of illness. Study of 101 schizo- phrenics found the four scales to be normally distributed and supported their reliability and stability. Posi- tive and negative scores were in- versely correlated once their common association with general psychopathology was extracted, suggesting that they represent mu- tually exclusive constructs. Review of five studies involving the PANSS provided evidence of its cri- terion-related validity with anteced- ent, genealogical, and concurrent measures, its predictive validity, its drug sensitivity, and its utility for both typological and dimensional assessment.

Schizophrenia has long been re- garded as a heterogeneous entity, and over the decades researchers have sought consistent subpattems that might explain different aspects of this complex disorder. Most re- cently, Crow (1980a, 1980b) and An- dreasen (1982; Andreasen and Olsen 1982) have proposed that two dis-

tinct syndromes in schizophrenia can be discerned from the phe- nomenological profiles. The Type I, or positive, syndrome is composed of florid symptoms, such as delu- sions, hallucinations, and disor- ganized thinking, which are superimposed on the mental status. The Type II, or negative, syndrome is characterized by deficits in cogni- tive, affective, and social functions, including blunting of affect and pas- sive withdrawal.

It has been speculated that these syndromes in schizophrenia bear etiological, pharmacological, and prognostic import. Thus, Crow (1980a) conceived of the positive symptoms as an aspect of hyper- dopaminergia (hence, a neuroleptic- responsive disorder) in contrast to a structural brain deficit that was thought to underlie the negative symptoms. The research to date has provided some indirect support for this model (e.g., Johnstone et al. 1976, 1978a, 19786; Andreasen and Olsen 1982), but the diversity of re- sults has defied clear-cut interpreta- tions. For example, Angrist, Rotrosen, and Gershon (1980) noted that one of the three negative symp- toms assessed improved with neu- roleptics, and Andreasen et al. (1982) found none of five negative symptoms to be associated with ventricular size as assessed by com- puted tomography of schizophrenic patients. The distinctiveness of the syndromes and their stability over different phases of illness also have been questioned. Whereas An- dreasen and Olsen (1982) contended that positive and negative syn- dromes are “at opposite ends of a continuum,” Pogue-Geile and Har-

Reprint requests should be sent to Dr. Stanley R. Kay, Research and Assess- ment Unit, Bronx Psychiatric Center, 1500 Waters PI., Bronx, NY 10461.

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262 SCHIZOPHRENIA BULLETIN

row (1984) observed a significant interrelationship during the posthospitalization phase. Linden- mayer, Kay, and Friedman (1986) further demonstrated that the exter- nal correlates of positive and nega- tive syndromes among acute schizophrenics change over the course of 2 years.

Research findings, of course, are at best only as reliable and valid as the measures on which they are based. Thus, a fundamental source of variability that can account for the disparate results is the instrument used for positive-negative assess- ment. Well-characterized and stand- ardized techniques are a clear prerequisite for meaningful study of these syndromes, their relationship to other features of schizophrenia, and their response to medication. Although several carefully con- ceived scales have been devised re- cently (e.g., Andreasen and Olsen 1982; Lewine, Fogg, and Meltzer 1983; Heinrichs, Hanlon, and Car- penter 1984; lager, Kirch, and Wyatt 1985), none have undergone the thorough process of psychometric standardization that is necessary to address fundamental, and as yet highly contested, issues of content and construct validity (Sommers 1985). It has also been a matter of concern that to achieve satisfactory reliability and validity, more rigor is needed in providing strict opera- tional criteria for eliciting, defining, and measuring symptoms (Zubin 1985). Other limitations in some of the reported methods include the following: (1) evaluation of the pres- ence but not severity of component symptoms, (2) imbalance in the number of items representing posi- tive and negative facets, (3) inap- plicability for both typological and dimensional assessment of syn- dromes, (4) no evidence of sen- sitivity for monitoring drug-related

changes, (5) no measurement of the relative preponderance of positive versus negative symptoms, and (6) no measure of general psycho- pathology and its possible influence on the severity of positive and nega- tive syndromes.

The purpose of this study was to develop and standardize a well-de- fined instrument for positive-nega- tive assessment that attends to these methodological and psychometric considerations. In addition, we rec- ognized the need for a procedure that can be applied in relatively brief time (40-50 minutes), with minimal retraining and reorientation for the clinician, and that can be used re- peatedly for longitudinal or psycho- pharmacological assessment. We re- port here on the development and initial standardization of the Positive and Negative Syndrome Scale (PANSS) involving 101 schizo- phrenics and review evidence of its validity from five separate studies.

Methods

Subjects and Design. Patients with an unqualified diagnosis of schizo- phrenia were surveyed to assess the distribution, reliability, construct va- lidity, and criterion-related validity of the PANSS. The medical charts of inpatients from long-term psychi- atric units in a university-affiliated urban hospital were screened con- secutively to select those having a formal DSM-III diagnosis of schizo- phrenia (American Psychiatric Asso- ciation 1980). All cases with questionable diagnosis, known organic disorder, or mental retarda- tion were excluded. The remainder were interviewed on their own wards by one of two research psy- chiatrists to ascertain independently whether patients met DSM-11I crite- ria for schizophrenia. If diagnoses were thus confirmed, patients un- derwent the semiformalized PANSS

interview (infra) and were then as- sessed on the PANSS scales plus a series of measures deriving from clinical interview, cognitive testing, motor assessment, and careful re- view of medical and historical rec- ords. These measures are described in separate articles that chiefly ad- dress their relationship to positive and negative syndromes (Kay, Opler, and Fiszbein 1986; Opler, Kay, and Fiszbein 1986).

The assessments were conducted by two research psychiatrists, one of whom collected data on 47 patients and the other on 54. Both psychia- trists first underwent intensive train- ing in the PANSS interview and rating methods until satisfactory team concordance was achieved, and subsequently they rated pa- tients individually. The raters held no a priori assumptions about the outcome of data and were unaware of results on the PANSS, which was undertaken before other measures but scored only after the conclusion of study.

The final sample consisted of 101 subjects of ages 20-68 (mean = 36.81, SD = 11.16), including 70 males, 31 females, 33 whites, 43 blacks, and 25 Hispanics. Twelve patients were married, 10 divorced, and the remainder single. Mean education was 10.09 years (SD = 2.92), with the range extending to 4 years of college in four cases. Twenty-nine subjects had a first-de- gree relative who was previously hospitalized for psychiatric treat- ment; schizophrenia was specified in five cases and affective disorder (depressive, manic, or bipolar) in 10 cases; alcohol abuse was reported in the nuclear family of 16 patients; and among 13 subjects there was ev- idence of family sociopathy, as judged by record of criminal be- havior and prosecution.

On the average, patients were

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VOL 13, NO. 2,1987 263

first hospitalized at age 22.39 years (SD = 8.63) and had since been ill for 14.41 years (SD = 8.95), with a median of six separate admissions. Over the past year and a half, 67.4 percent of the sample experienced continuous hospitalization, while for the remainder the mean duration of inpatient stay was 195 days. All were receiving neuroleptic medica- tion in standard dose ranges at the time of study.

Assessment Procedure. The PANSS ratings are based on all information pertaining to a specified period, usually the previous week. The in- formation derives from both clinical interview and reports of primary care staff (if institutionalized) or family members. The latter is the es- sential source for assessing social impairment, including items of im- pulse control, hostility, passive withdrawal, and active social avoid- ance. All other ratings accrue from a 30- to 40-minute semiformalized psychiatric interview that permits direct observation of affective, mo- tor, cognitive, perceptual, atten- tional, integrative, and interactive functions. The interview may be conceptualized as involving four phases.1

In the first 10-15 minutes, patients are encouraged to discuss their his- tory, circumstances surrounding their hospitalization, their current life situation, and their symptoms. The object of this phase is to estab- lish rapport and allow the patient to express areas of concern. Therefore, the interviewer at this point as- sumes a nondirective, unchallenging

•Full text of the PANSS Rating Man- ual, which includes the interview proce- dure, item definitions, anchoring point descriptions, and rating form, is avail- able on request from the authors.

posture to observe, as unobtrusively as possible, the nature of thought processes and content, judgment and insight, communication and rapport, and affective and motor re- sponses.

Deviant material from the first segment of the interview is probed during the second phase, lasting an- other 10-15 minutes, through pro- totypic leading questions that progress from unprovocative, non- specific inquiry (e.g., How do you compare to the average person? Are you special in some ways?) to more direct probe of pathological themes (e.g., Do you have special or un- usual powers? Do you consider yourself famous? Are you on a spe- cial mission from God?). The object now is to assess productive symp- toms that can be judged from the patient’s report and elaborations thereof, such as hallucinations, de- lusional ideation, suspiciousness, and grandiosity. For this purpose, the interviewer attempts to establish first the presence of symptoms and next their severity, which is gener- ally weighted according to the prominence of abnormal manifesta- tions, their frequency of occurrence, and their disruptive impact on daily functioning.

The third and most focused phase of the interview, requiring another 5-10 minutes, involves a series of specific questions to secure informa- tion on mood state, anxiety, orienta- tion to three spheres, and abstract reasoning ability. The evaluation of abstract reasoning, for example, consists of a range of questions on concept formulation (e.g., How are a train and bus alike?) and proverb interpretation, which are varied in content when using the PANSS for repeated assessment.

After all the essential rating infor- mation is obtained, the final 5-10 minutes of the interview are allo-

cated for more directive and forceful probing of areas where the patient appeared defensive, ambivalent, or uncooperative. For example, a pa- tient who avoided forthright ac- knowledgment of having a psychiatric disorder may be chal- lenged for a decisive statement. In this last phase, therefore, the patient is subjected to greater stress and testing of limits, which may be nec- essary to proceed beyond the social demand characteristics inherent in the interview situation and to ex- plore susceptibility to disorganiza- tion.

The interview procedure thereby lends itself to observation of physi- cal manifestations (e.g., tension, mannerisms and posturing, excite- ment, and blunting of affect), inter- personal behavior (e.g., poor rapport, uncooperativeness, hos- tility, and impaired attention), cog- nitive-verbal processes (e.g., conceptual disorganization, stereo- typed thinking, and lack of spon- taneity and flow of conversation), thought content (e.g., grandiosity, somatic concern, guilt feelings, and delusions), and response to struc- tured questioning (e.g., disorienta- tion, anxiety, depression, and difficulty in abstract thinking).

Positive and Negative Syndrome Scale (PANSS). Data elicited by this assessment procedure are applied to the PANSS, a 30-item, 7-point rating instrument that has adapted 18 items from the Brief Psychiatric Rat- ing Scale (BPRS) (Overall and Gorham 1962) and 12 items from the Psychopathology Rating Schedule (PRS) (Singh and Kay 1975a). Each item on the PANSS is accompanied by a complete definition as well as detailed anchoring criteria for all seven rating points, which represent increasing levels of psychopathol- ogy: 1 = absent, 2 = minimal, 3 = mild, 4 = moderate, 5 = moderate-

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284 SCHIZOPHRENIA BULLETIN

severe, 6 = severe, and 7 = ex- treme. Four sample items from the PANSS appear in the Appendix, and scoring is performed on a sepa- rate rating form in consultation with the Rating Manual.

In assigning ratings, one first re- fers to the item definition to deter- mine presence of a symptom. The severity of an item, if present, is then judged by using a holistic per- spective in deciding which anchor- ing point best characterizes the patient’s functioning, whether or not all elements of the description are observed. The highest applicable rating point is always assigned, even if the patient meets criteria for lower ratings as well.

Of the 30 psychiatric parameters assessed on the PANSS, seven were chosen a priori to constitute a Posi- tive Scale, seven a Negative Scale, and the remaining 16 a General Psy- chopathology Scale (see table 3 for the listing of component items).

The selection of items was guided by five considerations, in the follow- ing order of importance: (1) Items must be consistent with the hypo- thetical construct, i.e., with the the- oretical concept of positive and negative psychopathology as repre- senting productive features super- added to the mental status vs. deficit features characterized by loss of functioning (cf. Andreasen and Olsen 1982). (2) As per Carpenter, Heinrichs, and Alphs (1985), items should comprise symptoms whose classification as positive or negative is unambiguous and which, by most accounts, are regarded as primary rather than derivative (as, for exam- ple, impaired attention, disorienta- tion, and preoccupation may be secondary to arousal disorder or hal- lucinations). (3) They should be rep- resentative of different spheres of functioning (e.g., cognitive, affec- tive, social, and communicative) to

optimize content validity. (4) To the extent possible, they should include symptoms consensually regarded as crucial to the definition of the posi- tive syndrome (e.g., hallucinations, delusions, and disorganized think- ing) and negative syndrome (e.g., blunted affect, emotional with- drawal, and apathetic social with- drawal). (5) For practical and psychometric reasons, such as facili- tating cross-comparisons and equal- izing reliability potential, the numbers of items included in the positive and negative scales should be the same.

Insofar as this approach was de- termined by theoretical and heuristic considerations, there was no cer- tainty that all chosen items would be equally well suited or that all suita- ble items had been chosen; the inter- nal validity of the scales’ composi- tion was to be determined em- pirically by the data herein assem- bled.

The General Psychopathology Scale was included as an important adjunct to the positive-negative as- sessment since it provides a separate but parallel measure of severity of schizophrenic illness that can serve as a point of reference, or control measure, for interpreting the syn- dromal scores. It was not assumed

that this scale is statistically or con- ceptually distinct from the positive- negative assessment (an issue which also was to be determined by this study), but only that it may be used as a yardstick of collective non- specific symptoms against which to judge severity of distinct positive and negative manifestations.

In addition to these three scales, a bipolar Composite Scale was con- ceived to express the direction and magnitude of difference between positive and negative syndromes. This score was considered to reflect the degree of predominance of one syndrome over the other, and its valence (positive or negative) may serve for typological characteriza- tion.

The PANSS is scored by summa- tion of ratings across items, such that the potential ranges are 7-49 for the Positive and Negative Scales and 16-112 for the General Psycho- pathology Scale. The Composite Scale is arrived at by subtracting the negative from positive score, thus yielding a bipolar index that ranges from -42 to +42.

Results

Distribution of Scores. Table 1 sum- marizes the distribution characteris- tics of the four scales from the

Table 1. Distribution characteristics of the PANSS for 101 schizophrenics

Distribution characteristics

Mean Median SD Range (potential)

Range (obtained) Skewness Kurtosis

Positive

18.20 18 6.08 7 to 49

7 to 32 .07

– .97

Negative

21.01 20 6.17 7 to 49

8 to 38 .48 .06

PANSS scale

Composite

– 2.69 – 2

7.45 – 4 2 to +42

– 2 5 to +13 – .45

.13

General psychopathology

37.74 36

9.49 16to112 19 to 63

.23 – .30

NotB—PANSS = Positive and Negative Syndrome Scale.

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VOL. 13, NO. 2,1987 265

Figure 1. Frequency polygraph of distributions on the 4 scales of the Positive and Negative Syndrome Scale (PANSS)

401-

30 ->oz LJJ

o ai OC u. 10 –

20 –

–

i—r i .

COMPOSITE POSITIVE NEGATIVE GENERAL PSYCHOPATHOLOGY

• A Jr\ ••••-••• K../-; ,̂x”x-,….

-25 -17 – 9 -1 15 23 31

PANSS SCORE

39 47 55 63

PANSS was examined using coeffi- cient a to analyze its internal consis- tency and the contribution of the component items. As detailed in table 3, each of the items making up the Positive and Negative Scales cor- related very strongly with the scale total (p < .001), and the mean item- total correlations of .62 and .70, re- spectively, far exceeded the cross- correlations of .17 (Positive items with Negative Scale) and .18 (Nega- tive items with Positive Scale). The a coefficients with single items re- moved ranged from .64 to .84, and no perceptible gain on either scale

PANSS, and the full spectrum of scores is illustrated in figure 1. All four measures exhibited a roughly normal distribution pattern, without substantial skewness or kurtosis. This observation suggested that the constructs in question represent typ- ical continua and that their measure- ment is amenable to parametric statistical treatment. The obtained range of scores in all cases was con- siderably less than the potential range, suggesting that the scales were of ample breadth to avoid ceil- ing restrictions. The medians of the Positive and Negative Scales were strikingly close (18 and 20, respec- tively), and therefore the Composite Scale, representing their differential, exhibited a median of -2, which indi- cated an almost equal contribution by positive and negative items.

On the basis of the normality of distribution, it was possible to convert raw scores for each of the PANSS scales to percentile ranks (table 2). This process enables provi- sional interpretation of individual scores with reference to a medicated chronic schizophrenic sample.

Internal Consistency and Test-Re- test Reliability. The reliability of the

Table 2. PANSS distribution based on sample of 101 schizophrenics: Conversion of raw scores to percentile ranks

Raw score on PANSS scale

Percentile rank

99.9 99 98 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 2 1 0.1

Positive

37 33 31 29 26 25 24 23 22 21 20 19 18 — 17 16 15 14 13 12 11 8 7

— —

Negative

40 36 34 32 29 28 27 26 25 24 23 22 21 — 20 19 18 17 16 15 14 11 8 7

—

Composite

21 15 13 10 7 5 4 3 2 1 0

– 1 – 2 – 4 – 5 – 6 – 7 – 8 – 9 – 1 1 – 1 3 – 1 5 – 1 8 – 2 0 – 2 5

General psychopathology

67 60 58 54 50 48 46 44 43 42 40 39 38 36 35 34 33 31 30 28 26 22 18 16 —

Note—PANSS – Positive and Negative Syndrome Scale.

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266 SCHIZOPHRENIA BULLETIN

Table 3. Internal reliability analysis of

Individual scale Hems

Positive Scale Delusions Conceptual disorganization Hallucinatory behavior Excitement Grandiosity Suspiciousness Hostility

Scale total

Negative Scale Blunted affect Emotional withdrawal Poor rapport Passive-apathetic social withdrawal Difficulty in abstract thinking Lack of spontaneity & flow of conversation Stereotyped thinking

Scale total

General Psychopathology Scale Somatic concern Anxiety Guilt feelings Tension Mannerisms & posturing Depression Motor retardation UncooperatJveness Unusual thought content Disorientation Poor attention Lack of judgment & insight Disturbance of volition Poor impulse control Preoccupation Active social avoidance

Scale total

the PANSS

Mean

3.18 3.03 2.50 2.35 2.36 2.70 2.10

18.20 (

2.94 3.03 2.58 2.78 3.95 2.87 2.90

21.01 (

2.39 2.43 1 1.72 1 2.35 1 1.54 1 1.90 2.09 1 2.11 1 3.42 1 2.09 1 2.45 1 3.82 1 2.10 1 2.17 1 2.71 1 2.48 1

SD

1.52 .42 .70 .24 .56 .24 .14

5.08

.93 1.08 1.44 1.19 1.34 .45 .30

5.17

.21

.20

.06

.19

.12

.97

.10

.21

.49

.14

.28

.31

.30

.31

.18

.18 37.74 9.49

Item-total correlation

.78

.48

.66

.55

.64

.61

.59 (a = .73, p<.001)

.63

.78

.76

.79

.61

.86

.50 (a = .83, p<.001)

.48

.60

.23

.70

.33

.24

.27

.51

.51

.42

.65

.35

.66

.66

.60

.43 (a = .79, p<.001)

P

<.001 <.001 <.001 <.001 <.001 <.001 <.001

<.001 <.001 <.OO1 <.001 <.001 <001 <.001

<.001 <.001 <.O2 <.001 <.001 <.O2 <.01 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001

a coefficient with Item deleted

.64

.73

.70

.71

.73

.69

.70

.81

.78

.79

.78

.82

.76

.84

.77

.77

.79

.76

.79