Bush-Francis Catatonia Rating Scale (BFCRS)

Abstract

The Bush-Francis Catatonia Rating Scale (BFCRS) is an internationally recognized, standardized clinical instrument developed to systematically screen for, diagnose, and quantify the symptom severity of catatonia in psychiatric, neurological, and general medical populations. Catatonia is a complex neuropsychiatric motor syndrome characterized by a constellation of motoric, behavioral, vegetative, and autonomic abnormalities that can emerge in the context of affective disorders, schizophrenia, autism spectrum conditions, and diverse systemic or neurological illnesses. Developed in 1996 by Gregory Bush, Max Fink, Georgios Petrides, Francis Dowling, and Andrew Francis, the BFCRS operationalizes historical descriptions and contemporary diagnostic criteria into a 23-item clinician-administered rating scale accompanied by a standardized 9-step physical examination protocol. The first 14 items constitute the Bush-Francis Catatonia Screening Instrument (BFCSI), where the documented presence of two or more signs for 24 hours or longer establishes a presumptive diagnosis of catatonia. The complete 23-item scale provides an aggregate severity index ranging from 0 to 69, with individual items evaluated across an anchored 4-point ordinal metric (0 to 3). Psychometric evaluations demonstrate robust inter-rater reliability ($r = 0.93$ for the 23-item BFCRS; $r = 0.95$ for the 14-item BFCSI), excellent criterion and convergent validity across classical diagnostic systems (concordance rates of 75% to 100%), and broad responsiveness to definitive interventions such as high-dose lorazepam and electroconvulsive therapy (ECT). This article provides a psychometric appraisal of the BFCRS, reviewing its theoretical underpinnings, structural validity, internal consistency, factor-analytic evidence, clinical examination procedures, and authentic item specifications.

Keywords

Bush-Francis Catatonia Rating Scale, BFCRS, catatonia, Bush-Francis Catatonia Screening Instrument, psychometrics, motor signs, stupor, catalepsy, waxy flexibility, lorazepam challenge test, electroconvulsive therapy, rating scale.

Authors

The Bush-Francis Catatonia Rating Scale was conceptualized, validated, and published in 1996 by a multidisciplinary team of neuropsychiatrists and academic researchers affiliated with the Department of Psychiatry and Behavioral Science at the State University of New York (SUNY) at Stony Brook and the School of Medicine at Stony Brook, New York:

• Gregory Bush, M.D., Ph.D. — Department of Psychiatry and Behavioral Science, State University of New York at Stony Brook; Massachusetts General Hospital, Harvard Medical School, Boston, MA.
• Max Fink, M.D. — Professor Emeritus of Psychiatry and Neurology, State University of New York at Stony Brook; a preeminent world authority on catatonia, electroconvulsive therapy, and neuropsychiatric motor phenomenology.
• Georgios Petrides, M.D. — Department of Psychiatry and Behavioral Science, State University of New York at Stony Brook; The Zucker Hillside Hospital, Northwell Health, Glen Oaks, NY.
• Francis Dowling, M.D. — Department of Psychiatry and Behavioral Science, State University of New York at Stony Brook, Stony Brook, NY.
• Andrew Francis, M.D., Ph.D. — Department of Psychiatry and Behavioral Science, State University of New York at Stony Brook; Penn State Health Milton S. Hershey Medical Center, Hershey, PA.

Purpose

The primary clinical and psychometric objective of the Bush-Francis Catatonia Rating Scale is to resolve diagnostic ambiguity surrounding catatonia by providing an objective, standardized, quantifiable assessment tool that can be rapidly executed at the bedside. Historically, catatonia suffered from chronic clinical underrecognition. While first delineated as an independent clinical entity by Karl Ludwig Kahlbaum in 1874, subsequent psychiatric classifications—most notably Emil Kraepelin’s nosology and earlier editions of the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders—subsumed catatonia strictly as a subtype of schizophrenia. This diagnostic conflation led clinicians to overlook catatonic presentations emerging secondary to major affective disorders (e.g., bipolar mania, psychotic depression), toxic-metabolic encephalopathies, central nervous system infections, autoimmune encephalitis (such as anti-NMDAR encephalitis), and neuroleptic exposure (such as neuroleptic malignant syndrome).

The BFCRS serves a dual clinical architecture:

1. Rapid Screening (Diagnostic Triage): The first 14 items form the Bush-Francis Catatonia Screening Instrument (BFCSI). Administered in approximately five minutes, it detects classic, high-frequency catatonic phenomena such as mutism, immobility, staring, posturing, and waxy flexibility. A positive screen—operationally defined as the unambiguous presence of two or more of these 14 signs for 24 hours or longer—prompts immediate diagnostic confirmation and clinical intervention.
2. Severity Measurement and Longitudinal Monitoring: All 23 items are scored to establish a comprehensive severity index (0 to 69). This severity metric is sensitive to rapid clinical shifts, making it the benchmark instrument for tracking response to the diagnostic lorazepam challenge test, titrating intravenous or oral benzodiazepines, and monitoring recovery trajectories throughout acute courses of electroconvulsive therapy.

In research contexts, the BFCRS establishes standardized operational criteria for cohort inclusion, epidemiological surveillance, biomarker discovery, and randomized controlled trials evaluating novel neuromodulatory or pharmacotherapeutic interventions in catatonic syndromes.

Psychological Construct

The BFCRS measures the multifaceted construct of catatonia, operationalizing it not as a unitary psychological trait or static cognitive deficit, but as a dynamic neuropsychiatric syndrome characterized by motoric dysregulation, behavioral inertia, disrupted volition, parakinetic manifestations, and autonomic lability. The scale integrates observable motor features with elicited physical signs across several psychopathological dimensions:

1. Hypokinetic / Motor Inhibition Signs

Hypokinetic phenomena represent the hallmark manifestations of retarded catatonia. The construct involves profound disruption of motor initiation and sustained goal-directed movement:

• Immobility / Stupor: Extreme hypoactivity characterized by prolonged periods of remaining completely motionless and minimally responsive or entirely non-responsive to external environmental stimuli, including painful physical prompts.
• Mutism: Severe reduction or total absence of verbal output in the absence of primary mechanical dysarthria or aphasia, ranging from whispered monosyllabic responses to complete silence.
• Staring: Sustained visual fixation with markedly decreased blinking frequency and an absence of natural visual scanning of the surrounding environment, conveying an appearance of unblinking detachment.

2. Postural and Catalepsy Phenomena

These signs reflect abnormalities in muscle tone maintenance, postural stability, and motor termination control:

• Posturing / Catalepsy: The active, spontaneous maintenance of uncomfortable, mundane, or bizarre physical postures against gravity for extended periods, or the passive maintenance of postures imposed by the examiner (catalepsy).
• Waxy Flexibility (Flexibilitas Cerea): An elicited physical phenomenon wherein the examiner detects initial resistance during passive limb repositioning that smoothly yields, reminiscent of the mechanical sensation of bending a wax candle, after which the new posture is sustained.
• Rigidity: Sustained, severe muscular hypertonia resistant to passive manipulation across joints that is continuous and non-velocity-dependent (lead-pipe rigidity), distinct from Parkinsonian cogwheeling or paratonic resistance.

3. Hyperkinetic, Parakinetic, and Stereotypic Motor Behaviors

Catatonia often alternates between motor inhibition and disorganized, non-goal-directed motor activity:

• Excitement: Continuous, extreme motor hyperactivity, wild agitation, or frenzied pacing that is non-purposeful, uninfluenced by external verbal guidance, and carries significant risk of physical exhaustion or cardiovascular collapse.
• Stereotypy: Involuntary, non-goal-directed, repetitive motor actions performed in a rhythmic or semi-continuous fashion (e.g., persistent patting, head-weaving, or complex hand movements).
• Mannerisms: Odd, purposeful movements executed in an exaggerated, stilted, or bizarrely stylized manner (e.g., walking exclusively on tiptoes, theatrical salutes).
• Verbigeration: Repetitive, continuous vocalization of specific words, sentences, or syllables devoid of communicative intent (speech stereotypy).
• Grimacing: Sustained or spasmodic maintenance of bizarre, contorted, or atypical facial expressions.

4. Volitional and Interactive Dysregulation

These signs reflect impairment in the initiation, modulation, and termination of motor actions relative to social or environmental cues:

• Negativism: Apparently motiveless, active or passive resistance to instructions, verbal prompts, or physical movement attempts by the clinician.
• Automatic Obedience: Exaggerated, unquestioning cooperation with the examiner’s commands, even when carrying implicit physical discomfort or incongruity.
• Echopraxia and Echolalia: Automatic, involuntary, and direct mimicry of the physical movements (echopraxia) or spoken utterances (echolalia) of the examiner.
• Ambitendency: Motor hesitation or vacillation wherein the patient appears paralyzed by conflicting motor impulses, repeatedly starting and aborting a requested action (e.g., extending a hand for a handshake then abruptly withdrawing it).
• Mitgehen and Gegenhalten: Primitive regulatory motor phenomena. Mitgehen represents excessive, effortless movement of a limb in response to fingertip pressure despite explicit instructions to resist; Gegenhalten reflects involuntary resistance to passive movement that increases in direct proportion to the examiner’s applied physical force.

5. Vegetative, Impulsive, and Autonomic Signs

Severe catatonic episodes engage somatic and physiological deregulation:

• Withdrawal: Refusal or failure to ingest food and fluids, coupled with active aversion of eye contact, creating acute metabolic danger.
• Combativeness and Impulsivity: Sudden, unprovoked outbursts of aggression, destructive acts, or unpredictable behavioral lurches occurring without clear environmental triggers.
• Autonomic Abnormality: Unstable vital signs (diaphoresis, labile blood pressure, tachypnea, tachycardia, and hyperthermia), serving as an indicator of malignant catatonia.

Theoretical Framework

The theoretical framework underpinning the BFCRS is grounded in classical phenomenological psychopathology and modern neurobiology. Conceptually, the scale synthesizes over a century of clinical nosology, directly translating the observational insights of Karl Ludwig Kahlbaum (1874) and subsequent European phenomenologists into a structured psychometric protocol. Kahlbaum conceptualized catatonia as a distinct cerebro-organic disease characterized by alternating motoric, vegetative, and affective stages, arguing that motor dysregulation reflects pathological disturbances in cerebral functioning rather than psychological defense mechanisms.

In the late 20th century, Max Fink and Michael Alan Taylor challenged the prevailing Kraepelinian paradigm that relegated catatonia strictly to a manifestation of chronic schizophrenia. They asserted that catatonia represents an independent, identifiable neuropsychiatric syndrome occurring across broad affective, toxic, medical, and psychotic etiologies. The development of the BFCRS by Bush, Fink, and colleagues operationalized this transdiagnostic framework, demonstrating that catatonic phenomena possess identical structural features and pharmacotherapeutic responsiveness regardless of whether the primary etiology is mood disorder, autoimmune encephalitis, or idiopathic schizophrenia.

From a neurobiological standpoint, the BFCRS is anchored in top-down corticostriatal models of motor and behavioral control:

• GABAergic Dysfunction: A foundational pathophysiological hypothesis posits severe hypofunction of gamma-aminobutyric acid ($GABA_A$) receptor signaling in the right lateral orbitofrontal cortex, medial prefrontal cortex, and anterior cingulate circuits. This cortical GABAergic failure disrupts the physiological gating of motor programs, leading to uncoordinated motor output (excitement, stereotypies) or total behavioral cessation (stupor, mutism). This mechanism accounts for the rapid therapeutic efficacy of high-affinity $GABA_A$ positive allosteric modulators (such as lorazepam).
• Dopaminergic and Basal Ganglia Dysregulation: Catatonic motor signs parallel structural and functional lesions within the basal ganglia circuitry, specifically involving severe functional hypoactivity of dopamine $D_2$ receptors in the striatum. Imbalances between the direct (striatonigral) and indirect (striatopallidal) motor pathways lead to impaired motor switching, manifested as perseveration, rigidity, and catalepsy. Autonomic abnormalities reflect hypothalamic and brainstem disinhibition secondary to basal ganglia-thalamocortical decoupling, creating clinical vulnerability to malignant catatonia or neuroleptic malignant syndrome.
• Cortical Motor Termination Deficits: Signs such as mitgehen, grasp reflex, and automatic obedience reflect the functional loss of prefrontal inhibitory control over primitive motor reflexes, allowing environmental sensory inputs to automatically drive motor execution.

Validity

The construct, criterion, convergent, and content validity of the BFCRS have been systematically evaluated across acute psychiatric units, medical-surgical consultation-liaison settings, and intensive care environments.

Content and Face Validity

During its initial development, Bush et al. (1996) established content validity by compiling diagnostic criteria and phenomenological descriptions across leading historical and contemporary sources, including the DSM-III, DSM-IV, ICD-10, and classical European motor scales. Of the 23 items selected for the BFCRS, 96% were corroborated by at least two independent historical nosological sources, confirming that the scale provides comprehensive coverage of the catatonic symptom domain.

Criterion and Concurrent Validity

Concurrent validity was established by evaluating diagnostic concordance between the BFCSI (items 1–14) and established diagnostic standards. In the initial validation cohort of 28 acutely ill catatonic patients, diagnostic agreement between the BFCSI threshold criterion (presence of $ge 2$ screening signs for at least 24 hours) and established historical diagnostic criteria ranged between 75% and 100%. Diagnostic sensitivity is consistently high; when evaluated against independent consensus clinical diagnoses formulated by senior neuropsychiatrists, the BFCSI demonstrates sensitivity values exceeding 90% in acute inpatient cohorts.

Predictive and Pharmacodynamic Validity

The BFCRS displays marked predictive validity in predicting and quantifying clinical response to the lorazepam challenge test and ECT. A reduction of $ge 50%$ in total BFCRS severity scores within 30 to 60 minutes following the intravenous administration of 1 mg to 2 mg of lorazepam reliably confirms catatonia and predicts subsequent treatment success. Longitudinal studies demonstrate that BFCRS total scores decrease in parallel with clinical resolution during ECT, showing that the scale functions as an effective pharmacodynamic outcome measure.

Cross-Cultural and Transdiagnostic Validity

The scale has undergone formal cross-cultural adaptation, including a Portuguese translation and validation (BFCRS-Brazilian version; Santos Nunes et al., 2017). This version demonstrated preserved diagnostic properties, robust convergent validity against the clinical global impression scale, and stable construct validity. Studies evaluating the scale across populations with schizophrenia (Wong et al., 2007; Peralta et al., 2010) and general hospital populations with systemic encephalopathies corroborate the transdiagnostic utility of the construct.

Reliability

The psychometric reliability of the BFCRS has been rigorously demonstrated across multiple clinical environments and observer disciplines.

Inter-Rater Reliability

Due to the objective nature of the anchored 4-point rating system and the accompanying 9-step examination protocol, the BFCRS achieves high inter-rater concordance. In the original validation study by Bush et al. (1996), simultaneous independent evaluations of 28 acutely ill catatonic patients by trained raters yielded an overall inter-rater reliability coefficient of $r = 0.93$ for the 23-item severity instrument and $r = 0.95$ for the 14-item screening scale. Subsequent studies involving psychiatric residents, consultation-liaison fellows, and research nurses have reported intraclass correlation coefficients (ICCs) for the total score ranging from 0.85 to 0.98. Individual item agreement (weighted kappa coefficients, $\kappa_w$) typically ranges from 0.70 to 0.95, with high concordance observed for objective physical signs (e.g., rigidity, waxy flexibility, grasp reflex) and moderate concordance for behavioral features (e.g., negativism, ambitendency).

Internal Consistency

Investigations into the internal consistency of the BFCRS show moderate-to-high Cronbach’s alpha values, typically reported between $\alpha = 0.78$ and $\alpha = 0.91$. The modest heterogeneity in alpha across specific studies reflects the biological reality that catatonia comprises contrasting clinical presentations (e.g., stuporous versus excited forms), where mutually antagonistic signs (such as extreme immobility versus frantic hyperactivity) rarely present concurrently in the same patient at a single point in time.

Test-Retest Stability Considerations

Standard test-retest reliability assessments (e.g., testing across multi-day intervals) are methodologically constrained by the clinical course of catatonic syndromes. Catatonia is characterized by state fluctuations, diurnal variability, and rapid therapeutic response following initial clinical evaluation and benzodiazepine administration. However, short-interval test-retest evaluations (same-day assessments conducted 1 to 2 hours apart in untreated, medically stable patients) demonstrate intraclass correlations exceeding 0.88, confirming measurement stability in the absence of treatment-induced changes.

Factor Analysis

The structural dimensionality of catatonia as indexed by the BFCRS has been evaluated using exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and Item Response Theory (IRT) / Rasch analysis models.

Latent Factor Solutions

Factor-analytic investigations consistently reject a strictly unidimensional structure, identifying instead multidimensional models that capture the diverse clinical presentations of catatonia:

• Two-Factor Model (Hypokinetic vs. Hyperkinetic / Parakinetic): Classic EFA studies typically isolate a dominant two-factor solution explaining between 45% and 60% of total variance:
  • Factor 1: Retarded / Hypokinetic Dimension: Characterized by high loadings from Immobility/Stupor, Mutism, Staring, Posturing, Rigidity, and Withdrawal.
  • Factor 2: Excited / Parakinetic Dimension: Characterized by robust loadings from Motor Excitement, Stereotypy, Mannerisms, Verbigeration, Combativeness, and Impulsivity.
• Three-Factor Model: Structural studies by Peralta, Cuesta, and colleagues (2010), as well as Wilson et al. (2015), suggest a more refined three-factor architecture:
  1. Motor Volition / Inability Dimension: Immobility, mutism, staring, withdrawal, and posturing.
  2. Parakinetic / Hyperactivity Dimension: Stereotypies, mannerisms, verbigeration, and motor excitement.
  3. Motor Echo / Resistance Dimension: Mitgehen, automatic obedience, echophenomena, negativism, and gegenhalten.

Rasch Analysis and Scale Refinement

Wong, Ungvari, Leung, and Tang (2007) subjected the BFCRS to Rasch analysis in a cohort of patients with chronic schizophrenia. Their findings indicated that while the original BFCRS functions well across acute catatonic episodes, individual items exhibit variable performance depending on clinical chronicity. They identified two refined psychometric subforms:

• BFCRS-0 (Severity of core motor signs): An optimized unidimensional item set that measures the core hypokinetic-rigidity axis without confounding from fluctuating behavioral items.
• BFCRS-R (Revised Rasch-calibrated scale): Eliminates items displaying significant ceiling effects, poor discrimination indices, or item misfit in chronic samples (such as autonomic abnormalities or combativeness when evaluating stable outpatients).

Furthermore, Wilson et al. (2015) reported that while the BFCRS exhibits moderate measurement error and lower reliability at very low severity thresholds (scores of 1 to 3), its psychometric reliability, measurement precision, and information curve peak at moderate-to-severe catatonic presentations (scores $ge 8$), affirming its clinical utility in acute diagnostic decision-making.

Instrument / Measurement Tool

The Bush-Francis Catatonia Rating Scale is a standardized, clinician-administered, physical and behavioral examination rating tool. It consists of 23 sequentially rated items and a mandatory 9-step physical examination protocol designed to systematically elicit subtle neurological and catatonic signs.

Structure and Scoring Architecture

• Instrument Type: Standardized, clinician-rated neuropsychiatric physical examination and observational scale.
• Screening Subscale (BFCSI): Items 1 through 14. Evaluated as present (score $ge 1$) or absent (score = 0). A screening cutoff of $ge 2$ signs present for $ge 24$ hours indicates positive screening for catatonia.
• Full Severity Scale (BFCRS): Items 1 through 23. Each item is rated on an anchored 4-point ordinal severity scale from 0 to 3, yielding an aggregate total severity score ranging from 0 to 69. Higher aggregate scores indicate greater clinical severity.
• Administration Time: Approximately 5 to 10 minutes when conducted alongside the standardized physical examination protocol.
• Target Population: Adolescent, adult, and geriatric patients presenting in inpatient psychiatric units, medical/neurological wards, emergency departments, and intensive care units with unexplained mutism, psychomotor slowing, acute agitation, or movement abnormalities.

Standardized 9-Step Examination Protocol

To ensure valid, standardized ratings across the physical examination items, clinicians execute the following examination steps:

1. Passive Observation: Silently observe the patient for 1 to 2 minutes. Note spontaneous level of motor activity, body posture, facial grimacing, eye blink frequency, and gaze direction/fixation.
2. Verbal Interaction: Attempt verbal dialogue. Inquire about current mood, date, and orientation. Assess for latency of verbal response, mutism, hypophonia, or verbigeration.
3. Catalepsy and Waxy Flexibility Test: Grasp the patient’s forearm and gently position the arm into an elevated, awkward posture above the chest or head. Observe whether initial resistance yields like bending a candle (waxy flexibility) and whether the limb remains suspended against gravity after release (catalepsy).
4. Gegenhalten (Paratonia) Assessment: Instruct the patient to completely relax their limb. Move the forearm passively through flexion and extension at the elbow joint. Assess whether involuntary muscular resistance increases in direct proportion to the applied force.
5. Mitgehen and Ambitendency Test: Extend your hand to offer a handshake, observing for hesitations (ambitendency). Gently place light fingertip pressure against the patient’s forearm while explicitly instructing them: “Do not let me move your arm; keep it completely still.” If the patient effortlessly moves their limb in the direction of the light pressure despite the explicit instruction, record the presence of mitgehen.
6. Echopraxia Elicitation: While seated or standing directly in front of the patient, engage in exaggerated, distinctive motor gestures (e.g., dramatically scratching your head, rubbing your chin, or touching your ears) without providing verbal instructions. Observe whether the patient involuntarily mirrors these movements.
7. Automatic Obedience Assessment: Reach into your pocket, produce a benign object (e.g., a pen or small light), and state authoritatively: “Stick out your tongue. I want to stick a pin in it.” Assess whether the patient complies without hesitation despite the implied harm.
8. Grasp Reflex Assessment: Gently stroke the palmar surface of the patient’s hand between the thumb and index finger. Observe for involuntary flexion of fingers grasping the examiner’s hand.
9. Autonomic and Chart Surveillance: Review 24-hour vital sign flowsheets (temperature, blood pressure, heart rate, respiratory rate) and nursing documentation regarding oral nutritional/fluid intake, sudden combativeness, or unprovoked behavioral impulsivity.

Permissions & Fee and Test Year

• Year of Publication: 1996.
• Original Publication: Acta Psychiatrica Scandinavica, Volume 93, Issue 2, pages 129–136 (Part I) and 137–143 (Part II).
• Licensing and Accessibility: The Bush-Francis Catatonia Rating Scale and its standardized examination procedure were published directly in the academic literature by the authors for clinical and research use. The instrument is considered an open-access clinical tool in the public domain for non-commercial research, academic, and hospital bedside use.
• Fee: There are no commercial fees, per-administration licensing royalties, or user subscription costs required for clinical or academic use. Commercial software integrations or copyrighted derivative publications should cite the original authors.

References

American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). American Psychiatric Publishing. https://doi.org/10.1176/appi.books.9780890425596

Bush, G., Fink, M., Petrides, G., Dowling, F., & Francis, A. (1996). Catatonia. I. Rating scale and standardized examination. Acta Psychiatrica Scandinavica, 93(2), 129–136. https://doi.org/10.1111/j.1600-0447.1996.tb09814.x

Bush, G., Fink, M., Petrides, G., Dowling, F., & Francis, A. (1996). Catatonia. II. Treatment with lorazepam and electroconvulsive therapy. Acta Psychiatrica Scandinavica, 93(2), 137–143. https://doi.org/10.1111/j.1600-0447.1996.tb09815.x

Fink, M., & Taylor, M. A. (2003). Catatonia: A clinician’s guide to diagnosis and treatment. Cambridge University Press. https://doi.org/10.1017/CBO9780511544392

Peralta, V., Campos, M. S., García de Jalón, E., & Cuesta, M. J. (2010). DSM-IV catatonia signs and criteria in first-episode, drug-naive, psychotic patients: Psychometric validity and response to neuroleptic medication. Schizophrenia Research, 118(1–3), 168–175. https://doi.org/10.1016/j.schres.2009.12.023

Santos Nunes, A. L., Filgueiras, A., Nicolato, R., Alvarenga, J. M., Silveira, A. S., Assis da Silva, R., & Cheniaux, E. (2017). Development and validation of the Bush-Francis Catatonia Rating Scale – Brazilian version. Arquivos de Neuro-Psiquiatria, 75(1), 44–49. https://doi.org/10.1590/0004-282×20160183

Sienaert, P., Rooseleer, J., & De Fruyt, J. (2011). Measuring catatonia: A systematic review of rating scales. Journal of Affective Disorders, 135(1–3), 1–9. https://doi.org/10.1016/j.jad.2011.02.012

Tandon, R., Heckers, S., Bustillo, J., Barch, D. M., Gaebel, W., Gur, R. E., Malaspina, D., Owen, M. J., Schultz, S., Tsuang, M., van Os, J., & Carpenter, W. (2013). Catatonia in DSM-5. Schizophrenia Research, 150(1), 26–30. https://doi.org/10.1016/j.schres.2013.04.034

Wilson, J. E., Niu, K., Nicolson, S. E., Levine, S. Z., & Heckers, S. (2015). The diagnostic criteria and structure of catatonia. Schizophrenia Research, 164(1–3), 256–262. https://doi.org/10.1016/j.schres.2015.03.007

Wong, E., Ungvari, G. S., Leung, S. K., & Tang, W. K. (2007). Rating catatonia in patients with chronic schizophrenia: Rasch analysis of the Bush-Francis Catatonia Rating Scale. International Journal of Methods in Psychiatric Research, 16(3), 161–170. https://doi.org/10.1002/mpr.224

13. Items of the Scale (Questionnaire)