Positive and Negative Syndrome Scale (PANSS)

Abstract

The Positive and Negative Syndrome Scale (PANSS) is a 30-item, clinician-administered, semi-structured clinical rating instrument developed by Stanley R. Kay, Lewis A. Opler, and Abraham Fiszbein in 1987. Engineered to evaluate the presence, absence, and severity of psychopathological symptoms in individuals diagnosed with schizophrenia and related psychotic spectrum disorders, the PANSS has evolved into the international gold-standard primary outcome measure in clinical trials, psychopharmacological research, and tertiary psychiatric assessments. The instrument operationalizes psychopathology across three distinct a priori subscales: the Positive Scale (7 items, assessing productive symptoms such as delusions, hallucinations, and conceptual disorganization), the Negative Scale (7 items, assessing deficit features including blunted affect, emotional withdrawal, and passive social withdrawal), and the General Psychopathology Scale (16 items, evaluating non-specific manifestations including somatic concerns, depression, anxiety, poor impulse control, and active social avoidance). Each item is rated on a standardized 7-point anchored Likert-type scale ranging from 1 (Absent) to 7 (Extreme), yielding total composite scores between 30 and 210, alongside a dimensional composite score calculated by subtracting the negative total from the positive total. Extensive psychometric evaluations demonstrate robust internal consistency (Cronbach’s alpha ranging from 0.73 to 0.83 across subscales), acceptable test-retest reliability ($r = 0.60$ to $0.80$), and excellent inter-rater reliability among certified raters (intraclass correlation coefficients generally exceeding 0.80). Although originally conceived under a triadic model, contemporary structural equation modeling and exploratory and confirmatory factor analyses consistently substantiate a five-factor dimensional structure (comprising Positive, Negative, Cognitive/Disorganization, Excited, and Depressed/Anxiety dimensions). Published across more than 40 languages under rigorous international translation guidelines, the PANSS represents a pivotal milestone in psychiatric epidemiology, neurobiological phenotype mapping, and the measurement of therapeutic efficacy in psychiatry.

Keywords

Positive and Negative Syndrome Scale, PANSS, Schizophrenia, Psychopathology, Positive Symptoms, Negative Symptoms, Psychometrics, Clinical Trials, Antipsychotic Efficacy, Factor Analysis, Inter-Rater Reliability, Psychiatric Rating Scales

Authors

The Positive and Negative Syndrome Scale was formally established and published by a collaborative research team based primarily at the Albert Einstein College of Medicine and the Bronx Psychiatric Center in New York:

• Stanley R. Kay, Ph.D.: Former Director of Psychology and Psychiatric Research at the Bronx Psychiatric Center and Professor in the Department of Psychiatry at the Albert Einstein College of Medicine, Bronx, New York, United States. Dr. Kay was a leading psychometrician and neurocognitive researcher who dedicated his career to refining symptom classification and cognitive assessment in psychotic illnesses.
• Lewis A. Opler, M.D., Ph.D.: Renowned academic psychiatrist, pharmacologist, and clinical investigator affiliated with the Columbia University College of Physicians and Surgeons, the New York State Psychiatric Institute, and the Long Island Jewish Medical Center. Dr. Opler was an internationally recognized authority on schizophrenia pharmacotherapy, clinical trial methodology, and rater training calibration.
• Abraham Fiszbein, M.D.: Clinical psychiatrist and researcher at the Albert Einstein College of Medicine and Bronx Psychiatric Center, contributing expertise in psychopharmacology, nosology, and the clinical standardization of diagnostic interviews for severe mental disorders.

Commercial distribution, global copyright oversight, and official international translations of the scale and its accompanying manuals are administered by Multi-Health Systems (MHS Inc.), located in Toronto, Ontario, Canada, and North Tonawanda, New York, USA.

Purpose

The principal objective behind the development of the Positive and Negative Syndrome Scale was to construct a psychometrically balanced, standardized, and sensitive clinical metric capable of evaluating the dual-polarity framework of schizophrenic pathology, alongside its broader psychiatric sequelae. Prior to the establishment of the PANSS, clinical assessment relied heavily on tools such as the Brief Psychiatric Rating Scale (BPRS), the Comprehensive Psychopathological Rating Scale (CPRS), or separate unstandardized inventories that suffered from psychometric imbalance, inadequate operational definitions of deficit phenomena, or marked floor and ceiling effects.

Kay and colleagues sought to rectify these systemic limitations by engineering an instrument capable of fulfilling several vital clinical and research functions:

• Inpatient Admission Baseline Assessment: Establishing an exhaustive baseline profile of psychotic severity, cognitive disturbance, affective flattening, and behavioral dysregulation upon an individual’s entry into acute or tertiary psychiatric facilities.
• Antipsychotic Trial Benchmarking: Serving as the universally recognized primary efficacy endpoint required by global regulatory agencies, including the United States Food and Drug Administration (FDA) and the European Medicines Agency (EMA), for the evaluation and approval of novel first-, second-, and third-generation antipsychotics.
• Longitudinal Treatment Monitoring: Tracking dynamic symptom trajectories over weeks, months, or years, allowing clinicians to evaluate the emergence of treatment resistance, partial response, functional remission, or clinical relapse.
• Differential Phenotypic Characterization: Distinguishing between predominantly productive (positive) and predominantly deficit (negative) subtypes of schizophrenia, thereby informing neurobiological studies, structural neuroimaging protocols, electrophysiological inquiries, and personalized psychosocial or cognitive rehabilitation regimens.

To ensure high standardization, the PANSS protocol integrates a formal 45-to-50-minute clinical interview—frequently conducted using the Structured Clinical Interview for the PANSS (PANSS-SCI)—supplemented by clinical observations and behavioral reports gathered from multidisciplinary ward staff, family members, or primary caseworkers via the Informant Questionnaire (IQ-PANSS). This dual-source methodology prevents the underreporting of severe negative deficit symptoms and behavioral agitation that cannot be captured solely through self-report or brief unstructured dialogue.

Psychological Construct

The PANSS is rooted in a multidimensional conceptualization of psychotic illness, explicitly modeling the clinical reality that schizophrenia is not a monolithic disorder characterized strictly by hallucinations and delusions, but rather a heterogeneous neurodevelopmental syndrome spanning diverse symptomatic domains. The instrument divides this spectrum into three structured psychological constructs:

1. The Positive Syndrome Construct (Items P1–P7)

The positive syndrome construct refers to productive psychopathological features—manifestations that represent an excess or distortion of normal psychological and perceptual functioning. These symptoms reflect neurochemical hyperdopaminergic dysregulation within the mesolimbic pathway:

• Delusions (P1): Infoxible, idiosyncratic beliefs unsupported by objective reality or cultural norms, spanning persecutory, somatic, referential, or grandiose themes.
• Conceptual Disorganization (P2): Disruption of the goal-directed flow of thought, characterized by derailment, tangentiality, loose associations, circumstantiality, or illogicality.
• Hallucinatory Behavior (P3): Perceptual experiences occurring without external stimuli, primarily auditory hallucinations, along with command, somatic, olfactory, or visual variants.
• Excitement (P4): Hyperactivity, behavioral acceleration, heightened emotional responsivity, or unchanneled kinetic energy.
• Grandiosity (P5): Exaggerated self-appraisal, delusional convictions of possessing extraordinary power, identity, wealth, or mystical authority.
• Suspiciousness/Persecution (P6): Hypervigilance, paranoid mistrust, and entrenched convictions that external entities harbor malicious intent toward the individual.
• Hostility (P7): Verbal aggression, resentment, overt anger, destructive outbursts, and interpersonal belligerence.

2. The Negative Syndrome Construct (Items N1–N7)

Conversely, the negative syndrome construct captures deficit features—the absence or attenuation of cognitive, affective, and behavioral functions that are normally present in healthy individuals. Frequently linked to mesocortical hypodopaminergic states, prefrontal hypofrontality, and neurodevelopmental structural anomalies, these features include:

• Blunted Affect (N1): Diminished emotional responsiveness, characterized by a lack of facial expression, monotone vocal inflection, reduced gestural dynamism, and unresponsive body posture.
• Emotional Withdrawal (N2): Deficits in interpersonal empathy, inability to engage emotionally with clinical interviewers or family, and an absence of spontaneous affective resonance.
• Poor Rapport (N3): Failure to establish interpersonal connectedness, manifest as avoidance of eye contact, failure to attune to the examiner, and interpersonal coldness.
• Passive/Apathetic Social Withdrawal (N4): Loss of interest and initiative in social interactions, diminishing engagement with occupational or recreational settings driven by apathy.
• Difficulty in Abstract Thinking (N5): Impairment in figurative, categorical, or abstract reasoning, manifest as concrete interpretations of proverbs and categorical categorization failures.
• Lack of Spontaneity and Flow of Conversation (N6): Poverty of speech (alogia), characterized by brief, unelaborated, slow, and mechanical verbal output.
• Stereotyped Thinking (N7): Rigidity of mental content, repetitive ideas, inflexibility in shifts of cognitive set, and perseveration.

3. The General Psychopathology Construct (Items G1–G16)

The General Psychopathology scale captures non-specific manifestations of psychiatric distress, neurocognitive dysregulation, behavioral instability, and affective turbulence that accompany psychotic processes:

• Affective Distress Domains: Manifest as Somatic Concern (G1), Anxiety (G2), Guilt Feelings (G3), Tension (G4), and Depression (G6).
• Motor and Volitional Disruption: Manifest as Mannerisms and Posturing (G5), Motor Retardation (G7), Disturbance of Volition (G13), and Poor Impulse Control (G14).
• Cognitive and Metacognitive Impairment: Manifest as Unusual Thought Content (G9), Disorientation (G10), Poor Attention (G11), Lack of Judgment and Insight (G12), and Preoccupation (G15).
• Interpersonal Maladaptation: Manifest as Uncooperativeness (G8) and Active Social Avoidance (G16), the latter distinguishing active behavioral retreat due to fear or paranoia from the passive apathy captured under N4.

Theoretical Framework

The architectural foundation of the PANSS is directly situated within the clinical and neurobiological paradigm shifts that occurred in academic psychiatry during the late 1970s and 1980s. Chief among these was the Type I / Type II dichotomous model of schizophrenia proposed by British neuropsychiatrist Timothy J. Crow in 1980.

Crow postulated that schizophrenia consists of two dissociable clinical syndromes possessing distinct underlying pathobiological substrates:

1. Type I Syndrome (The Positive Syndrome): Dominated by productive features (delusions, hallucinations, thought disorder), acute presentation, favorable response to classical dopamine $D_2$ receptor antagonists, intact cognitive capabilities, and presumed neurochemical etiology (specifically, hyperactive dopaminergic neurotransmission).
2. Type II Syndrome (The Negative Syndrome): Dominated by deficit features (alogia, affective flattening, avolition, social withdrawal), chronic progressive course, poor response to traditional neuroleptics, marked neuropsychological impairment, and presumed structural brain pathology (including ventricular enlargement, cortical atrophy, and dendritic spine loss).

Concurrently, Nancy C. Andreasen developed the Scale for the Assessment of Positive Symptoms (SAPS) and the Scale for the Assessment of Negative Symptoms (SANS), demonstrating that negative symptoms could be operationalized with clinical precision. However, Kay, Opler, and Fiszbein argued that conceptualizing positive and negative symptoms as mutually exclusive polar opposites or independent diagnostic entities oversimplified clinical reality. In clinical presentations, patients frequently manifest severe productive psychotic symptoms alongside debilitating deficit states.

The theoretical synthesis of the PANSS postulated that positive and negative syndromes represent two concurrent, semi-independent dimensions interacting across a background matrix of general psychopathology. Under this dimensional paradigm:

$$\text{Schizophrenic Psychopathology} = f(\text{Positive Dimension}, \text{Negative Dimension}, \text{General Dysregulation})$$

By assessing both poles concurrently on an identical 7-point psychometric gradient, the PANSS enabled investigators to compute a Composite Index ($P – N$), operationalizing whether a patient’s overall presentation is positive-dominant, negative-dominant, or balanced.

Validity

Extensive psychometric investigations have affirmed the robust validity of the PANSS across clinical settings, diagnostic criteria (DSM-III, DSM-IV, DSM-5, and ICD-10/ICD-11), and international cohorts.

Construct and Structural Validity

Construct validity was initially established by Kay, Opler, and Lindenmayer (1988) by demonstrating that scores on the Positive and Negative subscales were normally distributed and effectively differentiated distinct diagnostic groups. Positive symptoms predominated in acute psychiatric admissions, whereas negative symptoms were pronounced in chronically institutionalized cohorts.

Cuesta and Peralta (1995) verified that the PANSS subscales exhibit adequate construct differentiation, although they observed moderate cross-dimensional correlations between certain negative items and general cognitive impairments. Khan et al. (2013) applied Rasch model analysis to evaluate the metric invariance of the PANSS across six geo-cultural regions (including North America, Europe, Asia, and Latin America). Their findings confirmed that while item difficulties vary slightly across language barriers, the primary latent traits measured by the PANSS remain cross-culturally invariant.

Convergent and Criterion Validity

The criterion-related validity of the PANSS was demonstrated through concurrent administration alongside established psychometric instruments:

• Positive Subscale Convergence: Correlates strongly with the SAPS global score ($r = 0.77$ to $0.86$) and the positive symptom cluster of the BPRS ($r = 0.80$ to $0.90$).
• Negative Subscale Convergence: Demonstrates high correlation with the SANS total score ($r = 0.78$ to $0.88$), affirming that both instruments capture identical deficit phenomena despite minor operational differences.
• General Psychopathology Subscale Convergence: Shows high correlations with the Clinical Global Impressions (CGI) Severity scale ($r = 0.65$ to $0.75$) and the Hamilton Depression Rating Scale (HDRS) for affective items ($r = 0.60$).

Predictive and Discriminant Validity

The PANSS has demonstrated notable predictive validity regarding functional and pharmacological outcomes. Research systematically demonstrates that high baseline scores on the Negative Scale (particularly N1, N2, and N4) robustly predict poor long-term vocational functioning, reduced community re-integration, and resistance to standard pharmacotherapies. Conversely, high scores on the Positive Scale predict favorable acute response to dopamine-blocking neuroleptics and higher rates of short-term symptomatic remission (Kumari et al., 2017; Opler et al., 2006).

Reliability

The psychometric integrity of the PANSS is underscored by robust reliability coefficients reported across empirical studies and multi-center clinical trials.

Internal Consistency

Original validation data by Kay et al. (1987, 1988) alongside contemporary meta-analytic reassessments confirm satisfactory to high Cronbach’s alpha ($lpha$) across all three subscales:

• Positive Scale (P1–P7): $\alpha = 0.73$ to $0.82$ (Acceptable to Good)
• Negative Scale (N1–N7): $\alpha = 0.83$ to $0.91$ (Good to Excellent)
• General Psychopathology Scale (G1–G16): $\alpha = 0.79$ to $0.86$ (Good)
• Total PANSS Score (30 items): $\alpha = 0.87$ to $0.93$ (Excellent overall internal cohesion)

Test-Retest Stability

When evaluated in clinically stable outpatients over 3- to 7-day intervals, Pearson correlation coefficients demonstrate high temporal consistency:

• Positive Scale: $r = 0.80$
• Negative Scale: $r = 0.68$ to $0.82$
• General Psychopathology Scale: $r = 0.60$ to $0.78$

The slightly lower retest stability observed in the General Psychopathology subscale reflects the fluctuating nature of acute affective symptoms, including situational anxiety and environmental tension.

Inter-Rater Reliability

Because the PANSS relies upon clinical observation, formal rater training and calibration are required to secure high inter-rater reliability. In multi-center global clinical trials utilizing certified raters, the Intraclass Correlation Coefficients (ICC) are typically:

• Positive Scale: $\text{ICC} = 0.72$ to $0.88$
• Negative Scale: $\text{ICC} = 0.80$ to $0.91$
• General Psychopathology Scale: $\text{ICC} = 0.56$ to $0.77$
• Total PANSS Score: $\text{ICC} = 0.83$ to $0.92$

Rigorous rater training programs, often involving the scoring of videotaped interviews and standardized consensus audits, are deployed in pharmaceutical trials to minimize rater drift and prevent inflation of type II error.

Factor Analysis

Although the PANSS was operationalized based on an a priori three-scale architecture (Positive, Negative, and General Psychopathology), subsequent exploratory factor analyses (EFA) and confirmatory factor analyses (CFA) performed on thousands of patient profiles demonstrated that a triadic structure fails to fully accommodate the complex covariance patterns of the 30 items.

The Five-Factor Consensus Model

Beginning with the empirical findings of Lindenmayer et al. (1994), Marder et al. (1997), and subsequent psychometric syntheses by Wallwork et al. (2012) and van der Gaag et al. (2006), research has established that the PANSS is best explained by a five-factor model. The widely validated Wallwork 20-item consensus model exemplifies this structure, exhibiting high goodness-of-fit indices (CFI > 0.95, RMSEA < 0.05):

Confirmatory factor analyses indicate that while the original 30-item, 3-subscale model retains substantial administrative value for clinical drug approvals, the five-factor model demonstrates superior structural fit and phenotypic sensitivity in psychiatric genetics, biomarker investigations, and cognitive profiling.

Instrument / Measurement Tool

• Instrument Name: Positive and Negative Syndrome Scale (PANSS)
• Alternate Standardized Variants:
  • Structured Clinical Interview for the PANSS (PANSS-SCI): Provides prescribed probes and dialogue paths.
  • Informant Questionnaire for the PANSS (IQ-PANSS): Gathers secondary behavioral observations from nursing staff, social workers, or family.
• Administration Modality: Clinician-rated semi-structured psychiatric interview combined with collateral informant observation.
• Administration Time: Approximately 45 to 50 minutes for the clinical interview, with an additional 15 to 20 minutes allocated for informant consultation and scoring.
• Target Clinical Population: Adults (aged 18–65+) diagnosed with schizophrenia, schizoaffective disorder, schizophreniform disorder, or other psychotic spectrum disorders.
• Total Item Count: 30 items divided into three subscales:
  • Positive Scale: 7 items (P1 through P7)
  • Negative Scale: 7 items (N1 through N7)
  • General Psychopathology Scale: 16 items (G1 through G16)
• Response Scale: 7-point rating scale with operationalized behavioral criteria for each severity tier:
  • 1 = Absent: The symptom is clearly not present; behavior is within normal limits.
  • 2 = Minimal: Questionable, subtle, or suspected pathology; may represent the upper border of normal variation.
  • 3 = Mild: Symptom is definitely present but occurs infrequently or with minimal functional disruption.
  • 4 = Moderate: The symptom is clearly manifest and interferes with daily functioning, thinking, or interpersonal rapport.
  • 5 = Moderate severe: The symptom exerts pronounced disruption across multiple life or cognitive domains.
  • 6 = Severe: Major disruption of life, thinking, or social integration; pervasive psychopathological intrusion.
  • 7 = Extreme: The symptom is incapacitating, catatonic, acutely dangerous, or profoundly disruptive to reality testing.
• Scoring and Computational Rules:
  • Subscale Scores: Derived by summing item ratings:
    • Positive Scale Score = $\sum (\text{P1 to P7})$, theoretical range: 7 to 49.
    • Negative Scale Score = $\sum (\text{N1 to N7})$, theoretical range: 7 to 49.
    • General Psychopathology Scale Score = $\sum (\text{G1 to G16})$, theoretical range: 16 to 112.
  • Total PANSS Score: Sum of all 30 items:
    $$\text{Total Score} = \text{Positive Score} + \text{Negative Score} + \text{General Psychopathology Score}$$
    Theoretical range: 30 to 210. (A score of 30 reflects an asymptomatic baseline).
  • Composite Scale Score: Calculated by subtracting the Negative subscale sum from the Positive subscale sum:
    $$\text{Composite Score} = \text{Positive Scale Total} – \text{Negative Scale Total}$$
    Theoretical range: $-42 \text{ to } +42$. Positive values denote positive symptom predominance, while negative values denote negative symptom predominance.

Permissions & Fee and Test Year

The Positive and Negative Syndrome Scale was first formally published in 1987 by Stanley R. Kay, Lewis A. Opler, and Abraham Fiszbein in Schizophrenia Bulletin, followed by the comprehensive test manual and standardized rating materials published in 1991 and revised in 2006.

Copyright and Commercial Licensing:
The copyright and commercial proprietary rights to the official PANSS manual, scoring protocols, PANSS-SCI, and certified translation kits are owned exclusively by Multi-Health Systems Inc. (MHS). The PANSS is a commercial clinical instrument; neither the test forms nor the scoring manuals reside in the public domain.

Commercial and Academic Usage Fees:
Researchers and clinicians wishing to employ the PANSS must purchase authorized interview booklets, response sheets, and scoring manuals directly from MHS or authorized distributors. In pharmaceutical clinical trials and funded research, fees are charged per administration or per protocol license. Academic researchers may apply for reduced-cost student or institutional research licenses through MHS.

Rater Certification and Training:
To ensure valid score profiles and fulfill FDA/EMA clinical trial guidelines, commercial raters must complete formal PANSS training and calibration programs, such as those provided by the PANSS Institute, WCG Clinical Endpoint Solutions, or certified academic research organizations, which grant official rater certification upon demonstrating inter-rater concordance (ICC ≥ 0.80).

References

• Canadian Agency for Drugs and Technologies in Health. (2011). A systematic review of combination and high dose atypical antipsychotic therapy in patients with schizophrenia. Ottawa: CADTH. https://www.ncbi.nlm.nih.gov/books/NBK169018/
• Crow, T. J. (1980). Molecular pathology of schizophrenia: More than one disease process? British Medical Journal, 280(6207), 66–68. https://doi.org/10.1136/bmj.280.6207.66
• Cuesta, M. J., & Peralta, V. (1995). Psychopathological dimensions in schizophrenia. Schizophrenia Bulletin, 21(3), 473–482. https://doi.org/10.1093/schbul/21.3.473
• Kay, S. R., Fiszbein, A., & Opler, L. A. (1987). The Positive and Negative Syndrome Scale (PANSS) for schizophrenia. Schizophrenia Bulletin, 13(2), 261–276. https://doi.org/10.1093/schbul/13.2.261
• Kay, S. R., Opler, L. A., & Lindenmayer, J. P. (1988). Reliability and validity of the Positive and Negative Syndrome Scale (PANSS) in schizophrenia. Schizophrenia Bulletin, 14(2), 261–276. https://doi.org/10.1093/schbul/14.2.261
• Kay, S. R., Opler, L. A., & Fiszbein, A. (2006). Positive and Negative Syndrome Scale (PANSS) manual. Multi-Health Systems, Inc.
• Khan, A., Yavorsky, C., Liechti, S., Opler, M., Rothman, B., DiClemente, G., Lucic, L., Jovic, S., Inada, T., & Yang, L. (2013). A Rasch model to test cross-cultural validity in the Positive and Negative Syndrome Scale (PANSS) across six geo-cultural groups. BMC Psychiatry, 13, Article 343. https://doi.org/10.1186/1471-244X-13-343
• Kumari, S., Malik, M., Florival, C., Manalai, P., & Sonje, S. (2017). An assessment of five (PANSS, SAPS, SANS, NSA-16, CGI-SCH) commonly used symptoms rating scales in schizophrenia and comparison to newer scales (CAINS, BNSS). Journal of Addiction Research & Therapy, 8(3), Article 324. https://doi.org/10.4172/2155-6105.1000324
• Lindenmayer, J. P., Bernstein-Hyman, R., & Grochowski, S. (1994). Five-factor model of schizophrenia: Replication across samples. Schizophrenia Research, 14(3), 229–234. https://doi.org/10.1016/0920-9964(94)90046-5
• Marder, S. R., Davis, J. M., & Chouinard, G. (1997). The effects of risperidone on the five dimensions of schizophrenia derived by factor analysis: Combined results of the North American trials. The Journal of Clinical Psychiatry, 58(12), 538–546. https://doi.org/10.4088/JCP.v58n1205
• Maust, D., Cristancho, M., Gray, L., Rushing, S., Tjoa, C., & Thase, M. (2012). Psychiatric rating scales. In Kaplan and Sadock’s Comprehensive Textbook of Psychiatry (10th ed.). Wolters Kluwer.
• Opler, L. A., Opler, M. G., & Malaspina, D. (2006). Reducing guesswork in schizophrenia treatment: PANSS can target and gauge therapy, predict outcomes in clinical practice. Current Psychiatry, 5(11), 76–84.
• Taylor, G. W., McCarley, R. W., & Salisbury, D. F. (2013). Early auditory gamma band response abnormalities in first hospitalized schizophrenia. Clinical Neurophysiology, 124(7), 131–145. https://doi.org/10.1016/j.clinph.2012.12.045
• van der Gaag, M., Cuijpers, A., Hoffman, T., Gulliksen, M., Benlakhel, F., Braakman, A., Slooff, C., & Wiersma, D. (2006). The five-factor model of the Positive and Negative Syndrome Scale (PANSS) in large samples with schizophrenia spectrum disorders: A comparison of three models. Schizophrenia Research, 85(1–3), 195–203. https://doi.org/10.1016/j.schres.2006.03.021
• Wallwork, R. S., Fortgang, R., Hashimoto, R., Weinberger, D. R., & Dickinson, D. (2012). Searching for a consensus five-factor model of the Positive and Negative Syndrome Scale for schizophrenia. Schizophrenia Research, 137(1–3), 246–250. https://doi.org/10.1016/j.schres.2012.01.031

13. Items of the Scale (Questionnaire)