Describing the Features of Catatonia: A Comparative Phenotypic Analysis

Abstract

Background

Catatonia is widely under-detected, and the many differences across catatonia rating scales and diagnostic criteria could be a key reason why clinicians have a hard time knowing what catatonia looks like and what constitutes each of its features.

Methods

This review begins by discussing the nature of catatonia diagnosis, its evolution in ICD and DSM, and different approaches to scoring. The central analysis then provides a descriptive survey of catatonia’s individual signs across scales and diagnostic criteria. The goal of this survey is to characterize distinctions across scales and diagnostic criteria that can introduce variance into catatonia caseness.

Results

Diagnostic criteria for catatonia in DSM-5-TR and ICD-11 are broadly aligned in terms of which items are included, item definitions and number of items required for diagnosis; however, the lack of item thresholds is a fundamental limitation. Many distinctions across scales and criteria could contribute to diagnostic discordance.

Discussion

Clear, consistent definitions for catatonia features are essential for reliable detection. Of available scales, Bush-Francis and Northoff can be converted to diagnostic criteria with limited modification. Bush-Francis is the most efficient, with a screening instrument, videographic resources and standardized clinical assessment. Northoff offers the most detailed assessment and uniquely emphasizes emotional and volitional disturbances in catatonia.

Conclusions

The field’s understanding of the catatonia phenotype has advanced considerably over the past few decades. However, this review reveals many important limitations in the ICD and DSM as well as differences across scales and criteria that stand in the way of reliable catatonia detection.

1. Introduction

Catatonia is a psychomotor syndrome that can present with too little (hypokinetic), too much (hyperkinetic), or abnormal (parakinetic) movement (Walther et al., 2019). As with commoner psychiatric syndromes like depression or anxiety, catatonia can present as a feature of primary mental illness or secondary to the physiological effects of a medical condition or psychoactive substance (American Psychiatric Association, 2022; World Health Organization, 2022). The syndrome of catatonia is heterogeneous, a fact to which a wide variety of diagnostic criteria and rating scales readily attest. There are significant discrepancies in terms of not only which items are included on criteria sets and rating scales but also, at a foundational level, how each item is defined. Even though the ICD-11 and DSM-5-TR (hereafter simplified as ICD and DSM, respectively) are now largely aligned, there yet remain important distinctions between them.

The diversity inherent in the catatonia syndrome is an important reason why catatonia is under-detected in clinical practice (Wortzel et al., 2021), and catatonia is relatively unique among psychiatric syndromes as its diagnosis relies almost exclusively on clinician ratings rather than self-report. In this regard, delirium, whose detection also relies on clinician ratings, offers a meaningful analog when considering the impact of different phenotypic definitions. For instance, comparisons between delirium rating scales and diagnostic criteria as well as between subsequent editions of the DSM can lead to substantial diagnostic discordance (Adamis et al., 2015; Meagher et al., 2014). These issues are just as relevant to catatonia whose diagnostic structure remains an area of ongoing investigation (Wilson et al., 2015). Moreover, the fact that catatonia’s individual features have received multiple definitions (e.g., definitions of catalepsy and waxy flexibility across editions of DSM and ICD) all but guarantees discordance in catatonia classification across scales and sets of diagnostic criteria. The goals of this phenotypic analysis are to contextualize the current state of catatonia nosology and to identify sources of potential variance in scoring individual catatonia features.

1.1. Methods

This review begins by tracing the evolution of the construct of catatonia since operationalized criteria were first introduced in ICD and DSM systems. Following this is a discussion of the nature of catatonia diagnosis with a focus on whether and which criteria are either required or prioritized across sets of criteria and scales. Then, the various approaches to scoring individual items is reviewed, including considerations of both thresholds and severity ratings.

The phenotypic analysis that follows compares individual catatonic findings to identify potential discrepancies that can lead to discordant classification. Included in this analysis are the latest edition of the ICD and DSM and clinically validated catatonia rating scales, as these are most likely to be used in clinical and research settings: Bush-Francis Catatonia Rating Scale (Bush et al., 1996) (including its recent Training Manual and Coding Guide (Wortzel and Oldham, 2022)), Northoff Catatonia Rating Scale (Northoff et al., 1999), Bräunig Catatonia Rating Scale (Braunig et al., 2000), and Rogers Catatonia Scale (Starkstein et al., 1996). The Modified Rogers Scale (Lund et al., 1991) is excluded here because it was originally validated only in schizophrenia. The Kanner scale (Carroll et al., 2008) is excluded as well because it has yet to be validated in a clinical population. Beyond catatonia rating scales, four additional sets of early-modern diagnostic criteria—Barnes (Barnes et al., 1986), Lohr-Wisniewski (Lohr and Wisniewski, 1987), Rosebush (Rosebush et al., 1990), and Fink-Taylor (Fink and Taylor, 2006)—will also be discussed for their visible role in the evolution of the field’s understanding of catatonia. Rosebush’s Appendix 1 (Rosebush et al., 1990) and Fink and Taylor’s chapter 2 (Fink and Taylor, 2006) also provide descriptions of catatonic features, which are included in the descriptive analysis that follows.

1.2. Evolution in the ICD and DSM

The conceptualization of catatonia has advanced considerably over the past few decades since DSM-III (American Psychiatric Association, 1980) and ICD-10 (World Health Organization (WHO), 1993), the editions of each system that first offered diagnostic criteria (Table 1). In DSM-III, catatonia was included only as a subtype of schizophrenia, and diagnosis required 1 of 5 features. DSM-IV (American Psychiatric Association, 1994) and IV-TR (American Psychiatric Association, 2000) broadened the diagnostic construct, allowing catatonia diagnosis in association with mood disorders or medical conditions but featured different sets of criteria for medical catatonia. ICD-10 characterized catatonia as an intermediate between DSM-III and DSM-IV.

Table 1:

Diagnostic criteria for catatonia in DSM and ICD

	DSM-IIIp191 (American Psychiatric Association, 1980) & DSM-III-Rp196 (American Psychiatric Association, 1987)	DSM-IVpp169,289,383 (American Psychiatric Association, 1994) & DSM-IV-TRpp185,315,417 (American Psychiatric Association, 2000)		DSM-5p120 (American Psychiatric Association, 2013) & DSM-5-TRp135 (American Psychiatric Association, 2022)	ICD-10pp59,81 (World Health Organization (WHO), 1993)		ICD-11 (World Health Organization, 2022)
Diagnoses	Schizophrenia	Schizophrenia		Schizophrenia	Schizophrenia		Schizophrenia
		Mood episode		Mood episode			Mood episode
				Neurodevelopmental			Neurodevelopmental
			Medical	Medical		Organic	Medical
							Substance
				Unspecified			Unspecified
Required number	1 of 5	2 of 5	1 out of a list	3 of 12	1 of 7	1 of 2	3 of 15
Catalepsy				X	Waxy flexibilityc		X
Waxy flexibility		Immobilitya	Immobilitya	X			X
Stupor	X			X	X	X	X
Mutism		Negativismb or mutism	X	X			X
Negativism	X		X	X	X		X
Posturing	X	Peculiarities of voluntary movement	Peculiarities of voluntary movement	X	X		X
Stereotypy				X			X
Mannerism				X			X
Grimacing				X			X
Echolalia		X	X	X			X
Echopraxia		X	X	X
Rigidity	X	As negativismb	As negativismb		X		X
Excitement	X	X	X	X	X	X	X
Impulsivity
Combativeness
Staring							X
Ambitendency							X
Verbigeration							X
Automatic obedience
Perseveration (verbal)					X

^aThe unifying feature is “immobility” as expressed by “catalepsy (including waxy flexibility)” or stupor. The term “immobility” is used in the criteria for medical catatonia without this parenthetical clarification, but one presumes a similar operationalization here as well. Curiously, the DSM-IV glossary defines catalepsy and waxy flexibility synonymously as posturing, with no comment about active vs passive induction.

^bThe description of negativism includes the traditional definition of negativism and of rigidity.

^cICD-10 includes “waxy flexibility” but defines it as “maintenance of limbs and body in externally imposed positions,” which is now widely described as catalepsy

In response to the limitations in previous catatonia definitions, DSM-5 introduced sweeping changes to the diagnosis of catatonia including, most notably, that its diagnostic criteria were unified across the DSM and a residual category “not otherwise specified” was created (Tandon et al., 2013). In line with these changes, DSM-5 (American Psychiatric Association, 2013), 5-TR,(American Psychiatric Association, 2022) and ICD-11 (World Health Organization, 2022) have viewed catatonia as a unique syndrome that deserves independent recognition. Each of these three sets of diagnostic criteria has included considerably more individual items of catatonia than forerunning systems; however, they have also increased the threshold for diagnosis to 3 criteria. Current editions of both DSM and ICD also acknowledge catatonia due to neurodevelopmental disorders in their descriptive text and an option for unspecified catatonia; ICD-11 alone recognizes a diagnosis of substance-induced catatonia. An additional change in ICD-11 was the creation of a new diagnostic category for catatonia at the same hierarchical level of, for instance, Mood disorders or Anxiety or fear-related disorders. One hopes that this advance will provide greater awareness and inspire enhanced clinical recognition.

1.3. Polythetic vs. nomothetic diagnosis

ICD, DSM, Bräunig, and Rogers are entirely polythetic, which means that any combination of criteria can count toward a catatonia diagnosis. Put differently, no single criterion or set of criteria must be present for diagnosis. Likewise, Bush-Francis takes a polythetic approach but adds a gated screening step into the assessment: the first 14 items serve as a screening instrument with the presence of any two or more screening items considered positive. A positive screen then prompts the clinician to continue scoring the remaining 9 items on the scale to obtain a full-scale score. Northoff takes a hybrid approach to diagnosis in that it categorizes catatonic features into behavior, motor, and affective symptoms and requires at least one finding in each category for catatonia diagnosis. Northoff not only includes a separate category of affective symptoms in catatonia but also requires at least one be present for diagnosis, so whereas the patient’s emotional experience in catatonia is highlighted the fact that an emotional symptom is required necessarily restricts catatonia to the subset of presentations with clinically evident emotional symptoms. The clinical implications of including emotions among catatonia’s diagnostic criteria deserves further investigation.

Thresholds for catatonia diagnosis vary across rating scales as well. Bräunig diagnosis of catatonia requires the presence of at least 4 items scored 2 (“moderate”) or higher, which means that any items rated as mild do not count toward diagnosis. Rogers requires a total scale score of 8 or greater. Per Bush-Francis, whereas the presence of at least 2 screening items is considered a positive screen, all subjects in the initial validation sample had at least 3 items on the screening scale suggesting that 3 items may be an appropriate threshold for diagnosis.

Rosebush, Barnes, Lohr-Wisniewski, and Fink-Taylor take a different approach to diagnosis, with each set of criteria prioritizing three core features and different sets of secondary features (Table 2). For instance, Rosebush describes the “cardinal” features of immobility, mutism, and withdrawal, and it defines catatonia as the presence of all three items. Alternatively, the presence of any two of these three cardinal features plus any two secondary features constitutes a diagnosis of catatonia per Rosebush. Strikingly, a review of the prioritized items on each of these four scales reveals that none is found on more than two scales: catalepsy (Barnes and Lohr-Wisniewski) and both immobility and mutism (on Rosebush and Fink-Taylor). These four sets of criteria—except for Fink-Taylor, whose Criterion B offers an alternate, polythetic set of criteria (see Table 2)—will yield substantively different determinations of catatonia than the current ICD and DSM criteria, which again are entirely polythetic. Whether certain features deserve diagnostic priority, and which these might be, remains an unanswered question.

Table 2:

Proposed diagnostic criteria, divided into primary and secondary signs

Barnes (Barnes et al., 1986)(a)	Lohr-Wisniewski (Lohr and Wisniewski, 1987)(b)	Rosebush (Rosebush et al., 1990)(c)	Fink-Taylor (Fink and Taylor, 2006)(d)
At least one of the following:  • Posturing  • Catalepsy  • Waxy flexibility	1. At least one of the following should be present:  a. Catalepsy  b. Positivism (such as automatic obedience, Mitmachen, Mitgehen)  c. Negativism	Cardinal features  • Immobility  • Mutism  • Withdrawal and refusal to eat or drink	A. Immobility, Mutism, or Stupor of at least 1 hour’s duration,…
Plus at least one of the following:  • Psychosocial withdrawal  • Excitement  • Mutism  • Negativism  • Impulsiveness  • Grimacing  • Stereotypies  • Mannerisms  • Command automatism  • Echopraxia/echolalia  • Verbigerations	2. At least two of the following should also be present:  a. Stereotypies  b. Mannerisms or grimacing  c. Bizarreries*  d. Posturing  e. Echo phenomena  f. Excessive muscular tension  g. Mutism  h. Staring	Secondary features  • Staring  • Rigidity  • Posturing/ grimacing  • Negativism  • Waxy flexibility  • Echolalia/ echopraxia  • Stereotypy	…associated with at least one of the following:  • Catalepsy,  • Automatic obedience, or  • Posturing,  observed or elicited on two or more occasions
	3. For a diagnosis of retarded or withdrawn catatonia, hypokinesia should dominate the clinical picture 4. For a diagnosis of excited catatonia, impulsiveness, combativeness, denuditaveness, or other signs of excessive activity should dominate the clinical picture.	Retarded catatonia might reasonably be diagnosed if there is either:  a. Coexistence of the three cardinal signs, or  b. Two cardinal signs plus at least two of the secondary features	B. In the absence of immobility, mutism, or stupor, at least two of the following, which can be observed or elicited on two or more occasions:  • Posturing  • Catalepsy  • Echophenomena  • Stereotypy  • Negativism  • Gegenhalten  • Ambitendency  • Automatic obedience

^(a)Barnes criteria derived from original publication.

^(b)Lohr-Wisniewski criteria used with permission of Guilford Publications, Inc., from Table 20-6. Tentative Criteria for the Diagnosis of Catatonia in Movement Disorders: A Neuropsychiatric Approach by Lohr J and Wisniewski AA. 1987; permission conveyed through Copyright Clearance Center, Inc.

^(c)Rosebush PI, Hildebrand AM, Furlong BG, Mazurek MF. Catatonic Syndrome in a General Psychiatric Inpatient Population: Frequency, Clinical Presentation, and Response to Lorazepam. The Journal of Clinical Psychiatry. 51, 357–362, 1990. Copyright 1990, Physicians Postgraduate Press. Reprinted by permission.

^(d)Fink-Taylor Proposed Diagnostic Criteria for Catatonia reprinted by permission from authors Drs. Fink and Taylor, from Catatonia: A Clinician’s Guide to Diagnosis and Treatment by Max Fink and Michael Alan Taylor. Cambridge, UK, Cambridge University Press, 2003. Content divided into rows for comparison with other diagnostic criteria.

^*Finding not defined, though in the chapter the term bizarre is noted under parakinetic catatonia, “dominated by bizarre, often jerky movements, sometimes resembling choreiform movements. There is frequent grimacing.”

1.4. Dichotomies, severity ratings, and hybrid approaches

Each individual item on ICD and DSM is categorical: either present or absent. A dichotomous approach to item recognition may be expected to reduce the likelihood of variance in scoring, provided all criteria were clearly defined with unambiguous thresholds. However, as explored in the following section, ICD and DSM do not include thresholds for any item (e.g., number of times a finding must be observed or the frequency or duration of a feature before it qualifies). Nor are any time periods specified over which findings must be present for diagnosis, despite the common clinical convention that catatonia be diagnosed based on findings present over 24 hours.

Each catatonia rating scale approaches thresholds differently as well, so caseness will vary based on the sensitivity of the definition of each item on each scale. Moreover, although all scales incorporate measures of item severity, they may be scored either to obtain a full score (i.e., sum of all individual item scores, accounting for severity) or as a count of items present (i.e., present at any severity), which could then be converted to diagnostic criteria in ICD or DSM.

Both Rogers and Northoff use an ordinal scale with three levels: 0 for absent, 1 for “definitely present,” and 2 for either “marked or pervasive” or “constantly and severely present,” respectively. Bräunig offers four severity levels for all items: minimal, moderate, marked, and severe (and, as above, only items scored as moderate or above count toward diagnosis on this scale). Gradations are generally defined based on duration, with blinking uniquely defined based on frequency. However, cutoffs for the severity of individual items vary widely. For instance, grimacing is graded “minimal” if observed for at least 10 sec whereas negativism and impulsiveness must be present for at least 5 min to qualify even as “minimal.” In all, there are 12 different sets of thresholds across its 21 items.

Each item on Bush-Francis can be scored ranging from 0 (absent) to 3 (severe); however, this scale takes a hybrid approach to severity scoring. Of its 23 items, 17 can be scored ordinally from 0 to 3, but 6 items are included as either “absent” (0 points) or “present” (3 points) as they are discrete findings (e.g., mitgehen and gegenhalten). The gradations are also variable across items: 7 are graded on the same basic scale (absent, occasional, frequent, constant; although the terms occasional and frequent are not defined in the original scale, the Training Manual describes occasional as “a couple of times” and frequent as “several”), 6 items include various numerical cutoffs for degrees of severity, and the remaining 4 divide severity descriptively. Finally, Fink and Taylor’s criterion A specifies an hour duration and identification of the finding(s) on at least 2 occasions, though the period between occasions is not specified.

2. Phenotypic analysis

What follows is a survey of individual items in ICD, DSM, and the four clinically validated catatonia rating scales (Table 3). Item descriptions from Rosebush and from Fink and Taylor are included as well. The sections below are divided into the three categories found in ICD with an additional section for autonomic abnormality.

Table 3:

Tabulation of individual catatonic features across diagnostic criteria and rating scales

	ICD-11 (World Health Organization, 2022)	DSM-5-TR (American Psychiatric Association, 2022)	Bush-Francis (Bush et al., 1996)	Northoff (Northoff et al., 1999)	Bräunig (Braunig et al., 2000)	Rogers (Starkstein et al., 1996)
Catatonia threshold	3 items	3 items	2 items*	1 item in each of 3 categories (motor, behavior, affect)	4 items scored at least “2” (moderate)	8 items
Abnormal psychomotor activity
Posturing	X	X	BF5	N.M7	B5	R1, R2
Catalepsy	X	X		N.M8	B15 “waxy flexibility”	R3
Waxy flexibility	X	X	BF13	N.M9
Rigidity	X		BF11	N.M10	B8
Gegenhalten			BF18	N.M6	B13
Grasp reflex			BF20
Hypotonus				N.M11
Tone alterations				N.M12
Mannerism	X	X	BF9	N.M1, N.B5	B17	R8	R14
Stereotypy	X	X	BF8	N.M2	B2
Grimacing	X	X	BF6	N.B1	B5	R6
Rituals					B21
Echolalia	X	X	BF7	N.B7	B12	R17
Echopraxia		X				R11
Mitgehen			BF17	N.B8		R4
Mitmachen
Gegengreifen
Verbigeration	X		BF10	N.B2	B4	R16
Compulsive speech				N.B4
Perseveration			BF21	N.B3, N.B9	B3 “iterations”	R10 “iterations”
Parakinesia				N.M3 “festination”	B14	R12, R13 (both gait-specific)
Dyskinesias				N.M5	B6 “jerky movements”	R5, R7
Athetosis				N.M4
Groping					B1
Blinking					B9
Decreased psychomotor activity
Stupor	X	X	BF2	N.M13 “akinesia” N.B13 “stupor” N.B14 inanition	B11	R19, R22 R9 “slowness”
Mutism	X	X	BF3	N.B12	B16	R15
Negativism	X	X	BF12	N.B10	B19	R20
Withdrawal			BF14	N.B11
Staring	X		BF4	N.A11
Ambitendency	X		BF19	N.A10 “ambivalency”
Flat affect				N.A7
Affective latency				N.A8
Increased psychomotor activity
Agitation	X	X	BF1 “excitement”	N.A5, N.A12, N.A6	B10	R18, R21
Emotional reactions				N.A1, N.A2, N.A9
Impulsivity	X		BF15	N.A3	B20
Combativeness	X		BF22	N.A4 “aggression”
Automatic obedience			BF16	N.B6	B18
Autonomic abnormality
Autonomic abnormality	(specifier)		BF23	N.B15 “vegetative abnormalities”

^*2 items on the Bush-Francis Catatonia Screening Instrument, which is the first 14 items on the scale.

2.1. Abnormal psychomotor activity

Motor and muscle tone

DSM and ICD agree on their definitions of posturing, catalepsy, and waxy flexibility. Posturing describes maintenance of a posture that is assumed by the patient in a spontaneous and active fashion. “Spontaneous” refers the origin of the finding in that it is not prompted by the examiner or environment. The term “active” differentiates posturing from catalepsy, which are body positions induced “passively” by the examiner or otherwise by the environment. Posturing must be against gravity, such that reclining postures on a bed without activation of muscles of the torso, extremities, or neck are excluded. ICD further notes that “sitting or standing for long periods without reacting” qualify as posturing; such motor expressions represent a subset of posturing as both sitting and standing require that muscles be engaged to keep one from falling. Catalepsy is the “passive” corollary to posturing: passive induction of a posture, also held against gravity.

Northoff defines posturing (N.M7) and catalepsy (N.M8) as separate items and defines them nearly identically to that of DSM and ICD (note: for comments regarding voluntariness and controllability see last paragraph in Discussion). Bush-Francis defines these terms similarly but combines them into a single item (BF5), making no distinction as to whether the position originated actively (posturing) or passively (catalepsy). Bräunig adds the descriptors “habitual” and “stereotyped” to posturing (B7) and specifies that muscular tone is limp upon examination; it then describes rigidity (B8) as a form of posturing with increased muscle tone. Bräunig reserves the term waxy flexibility (B15) to describe induced postures (i.e., catalepsy) and notes that this phenomenon may involve a “waxy” muscular resistance during repositioning. In other words, Bräunig considers these phenomena as symptom complexes rather than as individual symptoms; however, because these definitions combine features of motor and muscular tone, these items on Bräunig cannot be converted directly to diagnostic criteria without significant scoring modification. Rogers offers two forms of posturing—simple abnormal (R1) that is fixed and complex abnormal (R2) that “may be more dynamic,” including repeated or successive postures. Rogers includes catalepsy as “imposed postures” (R3) and, similar to Bräunig, describes “sustained” versions of this as waxy flexibility (see following paragraph). Rosebush defines posturing consistent with DSM and ICD. Fink and Taylor appear to describe posturing and catalepsy synonymously though list these separately in Criterion A (Fink and Taylor, 2006).

Waxy flexibility (flexibilitas cerea per Northoff) deserves special note because of its often incompletely overlapping definitions. Historical descriptions of waxy flexibility and catalepsy have long been intertwined to the extent that Rosebush describes them synonymously as induced postures and the DSM-III through DSM-IV-TR describe them synonymously as the symptom complex of induced postures with a characteristic waxy feeling when moving the patient’s limbs. DSM-5-TR, ICD-11 and Northoff (N.M9) describe waxy flexibility as “slight” and “even” resistance to positioning by the examiner. As such, it is an expression of increased muscular tone elicited on physical examination, thus representing a mild form of rigidity (see next paragraph). Bush-Francis and Fink-Taylor define waxy flexibility (BF13) as “initial resistance” before allowing oneself to be repositioned; as such, it can be only “present” or “absent.” Interestingly, Northoff and Bush-Francis/Fink-Taylor employ the idea of being similar to that of a bending candle yet define the phenomenon differently. As noted previously, Rogers describes sustained catalepsy as waxy flexibility, and Bräunig’s symptom complex definition for waxy flexibility (B15) may include “‘waxy’ muscular resistance,” but this is not required.

Rigidity is included in ICD as “resistance by way of increased muscle tone,” which can range from mild to severe. Curiously, whereas ICD describes severe rigidity as “lead pipe,” it fails to acknowledge that mild rigidity blends imperceptibly with waxy flexibility, per its own definition. DSM-5 and 5-TR do not include rigidity, though rigidity was included in DSM-III through IV-TR—and apparently as a feature of negativism in DSM-IV and IV-TR (see Table 1 footnote). Northoff defines rigidity (N.M10) as hypertonus that is either “even and steady” or “cogwheel-like,” but this overlaps with its definition of waxy flexibility where “slight and even” because “slight” and “mild” are near synonyms. Avoiding criterion overlap, Bush-Francis defines rigidity (BF11) as ranging from mild to severe but then defines waxy flexibility as an initial finding; Fink and Taylor similarly define waxy flexibility as initial stiffness on passive range of motion. Whereas both Bush-Francis and Northoff exclude tremor as counting toward rigidity, cogwheel rigidity is excluded by Bush-Francis but included by Northoff. As noted previously, rigidity in Bräunig is defined as a subtype of posturing. Rogers does not include rigidity; Rosebush defines rigidity consistent with ICD.

Gegenhalten (paratonic rigidity) is included by Northoff (N.M6), Bush-Francis (BF18) Bräunig (B13), and Fink-Taylor. In each, it describes resistance to passive movement proportion to the force applied. The syntax in Northoff for this item appears to suggest that this finding seems to be voluntarily controlled whereas Bräunig describes it as “apparently not willful.” Fink-Taylor describes gegenhalten similarly (though see also negativism). Three additional features of muscle tone are described. Grasp reflex (BF20) is described as “per neurological exam” on the Bush-Francis and similarly by Fink and Taylor. The Northoff includes muscular hypotonus (N.M11), described as “slack and loose” muscles on passive motion, and sudden muscular tone alterations (N.M12), which involves rapid switches in muscle tone.

A few notable scoring thresholds for items of motor and muscle tone are offered. Bush-Francis divides severity of posturing/catalepsy based on time with the cut-points at 1 and 15 minutes. Northoff requires that posturing and catalepsy be present for at least a minute before being scored, which means that historical descriptions of haltungsverharren (a brief maintenance of imposed postures (Fernandes, 1937)) would qualify for scoring in Bush-Francis as posturing/catalepsy but not Northoff. The severity of the two variants of posturing included on Bräunig (i.e., posturing and rigidity) are graded based on time with the cut-points of 2, 10, and 20 min. Bräunig grades the severity of induced postures (again, what it calls waxy flexibility) based on time with the cut-points of 10, 20, and 30 sec. Rogers specifies under rating instructions that a posture must be induced “more than once” to be scored as present.

Mannerism, stereotypy, grimacing

Three findings of abnormal psychomotor activity are included on both ICD and DSM: mannerism, stereotypy, and grimacing. Mannerism (singular per DSM, plural mannerisms per ICD) represents odd movements that represent a caricature of mundane (ICD) or normal (DSM) actions in both sets of criteria. Stereotypy is described as repetitive and non-goal-directed movements of an abnormally frequent nature. Grimacing is characterized by odd or distorted expressions in the face according to the ICD, but the finding is not included in DSM.

Each of the scales employ unique distinctions across these three signs. Mannerisms and stereotypy are described similarly by Bush-Francis (BF9 and BF8), Northoff (N.M1 and N.M2), Bräunig (B17 and B2), Rosebush, and Fink-Taylor. One distinction is that, according to the Bush-Francis Scoring Manual, manneristic speech qualifies as mannerisms whereas manneristic speech is scored as abnormal speech per Northoff (N.B5). There is no defined correlate of manneristic speech on the Bräunig. Rogers combines complex mannerisms and stereotypies but divides them into two items based on body region: face and head (R6) vs trunk and limbs (R7). Manneristic speech is scored as aprosodic speech (R14) on Rogers. Per the Bush-Francis Scoring Manual, grimacing (BF6) includes fixed facial expressions (akin to ‘posturing of the face’ per Fink and Taylor) or either stereotyped or manneristic facial expressions. Such facial expressions would be scored as grimacing (N.B1) on Northoff or either grimacing (B5) or complex mannerisms or stereotypies of the face and head (R6) on Rogers. Rosebush expounds upon grimacing as “snout spasms” (per Kahlbaum), “convulsive-type spasms,” and “tics,” apparently allowing for both fixed and repetitive facial expressions. Fink and Taylor describe stereotypy and mannerism as do ICD and DSM but notably include verbigeration (see below) as verbal stereotypy; grimacing is considered a type of facial posturing by Fink and Taylor. Bräunig and Rogers each contain an item called iterations (B3 and R10) described as repetitive spontaneous movements, though such descriptions would appear to represent variants of stereotypy or mannerism occurring over a longer period.

In terms of scoring thresholds, Northoff requires that an action be exhibited more than 3 times to qualify as a stereotypy. Bush-Francis grades severity of grimacing based on duration with cut-offs of 10 and 60 sec. Bräunig grades all three findings based on duration but recommends different cut-offs for each: mannerisms (5, 15, and 30 min), stereotypy (2, 10, and 20 min), and grimacing (10, 30, and 60 sec).

Echophenomena (echolalia and echopraxia), mitgehen/mitmachen, and gegengreifen

Echophenomena (singular echophenomenon) are included as a single item in ICD but separate items in DSM. In both nosologies, echolalia is described as mimicking speech and echopraxia as mimicking movements. Of limited but perhaps non-negligible consequence, ICD specifies that mimicry must be of the examiner whereas DSM allows for mimicking of “another” person, inclusive of other bystanders. Northoff, Bush-Francis, Rosebush and Fink-Taylor combine echolalia and echopraxia (N.B7 and BF7) whereas Rogers divides them into separate items (R17 and R11). Fink and Taylor also specify that echophenomena may occur spontaneously or persist despite instructions to the contrary.

Bräunig is unique in combining echophenomena with mitgehen/mitmachen (“exaggerated movements in response to light pressure,” see below) and gegengreifen (“repeated inviting gestures despite instructions to the contrary”) into a single item, labeled exaggerated responsiveness, copying (B12). Mitgehen is described as an individual item per Bush-Francis (BF17) and Rogers (R4); in both instances it is described as “anglepoise lamp” or the raising of an arm in response to light pressure “despite instructions to the contrary” (Bush-Francis) or “in the presence of an apparent grasp of the need to resist” (Rogers). Northoff combines mitgehen and mitmachen as a single item (N.B8) and offers unique definitions of each term: following others in an inappropriate way either in gait movements (mitgehen) or other actions (mitmachen). According to Northoff, mitgehen/mitmachen must occur more than 5 times over at least 3 min to be scored.

Verbigeration and perseveration

Not included in DSM, verbigeration is a diagnostic criterion in ICD described as “repetition of words, phrases, or sentences.” Per Bush-Francis (BF10), Northoff (N.B2), and Fink-Taylor, this item is described as the repetition of “phrases or sentences,” on Bräunig (B4) and Rosebush as “words or phrases” and the unit of repetition is unspecified on Rogers (R16). The idea of verbigeration as like that of “scratched record” (per Bush-Francis and Fink-Taylor) is consistent across the ICD and the four scales considered here. Northoff uniquely includes the feature increased, compulsive-like speech (N.B4), which is a hyperverbal phenomenon in an apparently involuntary fashion. The only threshold provided is by Bräunig, which specifies the following cutoffs for grading severity: 2, 10, and 20 min.

Bush-Francis and Northoff each include perseveration (BF21 and N.B3) described as repetitive actions/movements or thoughts/topics. The Bush-Francis Scoring Manual further specifies that perseveration does not occur spontaneously but is initiated by environmental stimuli, such as a handshake, a brief instruction, or a conversation. Northoff includes another similar feature called compulsive behavior (N.B9) described as “repetitive patterns (i.e., > 5 times) of behavior” that the person “feels driven to perform.” Similarly, Bräunig includes rituals (B21) “monotonous, driven, stereotyped repetition of complex behaviors and actions…performed on a regular daily basis.” The relationship of these items to perseveration or complex stereotypies is unclear as described. The one threshold provided is from Bräunig, which specifies the cutoffs for grading the severity of rituals as 5, 15, and 30 min.

Other signs of abnormal psychomotor activity

Several additional signs of abnormal psychomotor activity are included by Northoff, Bräunig, and Rogers. Abnormal gait is included on Northoff as festination (N.M3) (“uncoordinated, inappropriate, jerky-like, hasty movements”) and on Rogers as reduced associated movements during gait (R12) and slow/shuffling gait (R13). Bräunig’s item parakinesia (B14) does include abnormal gait but more broadly describes a generalized awkward or bizarre quality of all voluntary movements. Dyskinesias are included by Northoff (N.M5); Rogers includes dyskinesias either as affecting the face and head (R5) or trunk and limbs (R7). The item jerky movements on Bräunig (B6) appears to be an analog to dyskinesias with the severity cutoffs of 10, 30, and 60 sec. Two additional abnormal movements include Northoff’s athetotic movements (N.M4) (“movements with a screw-shaped character”) and Bräunig’s groping (B1) (“restless movements of hands and/or fingers”). Groping appears to include carphology/floccillation and perhaps utilization behavior (sometimes called hypermetamorphosis). One final item that may be considered an abnormal movement is blinking (B9) on Bräunig’s scale, which is an inverse expression of staring. The cutoffs for blinking severity are based on frequency: 30/min, 50/min, 70/min, and 90/min. Nearly all such items in this paragraph would be scored as either stereotypy or mannerisms on ICD, DSM, or Bush-Francis.

2.2. Decreased psychomotor activity

The hallmark feature of decreased activity, stupor, is included by both ICD and DSM. It describes a generalized immobility, no or markedly reduced psychomotor activity, or minimal responsiveness to external stimuli. All four scales reviewed here as well as Rosebush and Fink-Taylor include expressions of stupor. Bush-Francis describes this item as immobility/stupor (BF2). Northoff includes two separate items that appear to refer to largely overlapping constructs: akinesia (N.M13, “complete absence and paucity of movements”) and stupor (N.B13, no “psychomotor activity” and “does not actively relate to his or her environment”). Northoff also includes a third item with a similar expression, loss of initiative (N.B14), which describes an abulic state. Bräunig features motor inhibition (B11) (“state of hypoactivity”) whereas Rogers includes directly observed marked underactivity (R19) or reported underactive behaviour (R22). Rogers also features a similar item slowness/feebleness of spontaneous movements (R9), for which it provides the examples of “weak, languid, laboured,” which also appears to be on the spectrum of stupor. Rosebush includes immobility, described as “paucity or absence of spontaneous movements,” and Fink-Taylor describe stupor as a state of “unresponsiveness, hypoactivity, and reduced or altered arousal.” No thresholds are provided for any of these features, though it is at least noteworthy that DSM describes the finding as “no” psychomotor activity without explicitly allowing markedly reduced psychomotor activity to qualify. One nevertheless presumes such markedly reduced psychomotor activity would honor the spirit of this item.

Mutism is included in both diagnostic systems as well as all four scales, Rosebush, and Fink-Taylor. Both ICD and DSM describe mutism as “no” or “very little” verbal response, though thresholds for “very little” are not defined. ICD specifies further that “speech may be hushed or whispered to the point of being unintelligible.” Bush-Francis (BF3), Bräunig (B16) and Rogers (R15) have similar definitions that include a gradient from minimally responsive to entirely unresponsive (mute). Of the scales, only Bush-Francis and Bräunig also specify that “incomprehensible whispers” should be scored as mutism, as does Rosebush. Northoff restricts mutism (N.B12) to “no verbal responses,” and further requires that mutism persist for at least 30 minutes before being scored. Such a restrictive definition would need to be modified for converting to either ICD or DSM. Fink-Taylor describes mutism as “verbal unresponsiveness.”

Although featured in ICD, DSM, all four scales, Rosebush, and Fink-Taylor, negativism (negativismus per Northoff) has several notable differences of definition. Common to negativism across definitions is the idea of opposition or non-response to instructions or external stimuli. ICD and Bräunig (B19) also include withdrawal from interactions or refusal to take food or drink, a finding that would be scored on Bush-Francis and Rosebush separately as withdrawal (BF14). Both Bush-Francis and Rosebush include avoidance of “eye contact” with the examiner as a feature of withdrawal, and Rosebush further specifies that withdrawal includes “turning away from the examiner.” Fink and Taylor describe gegenhalten as the motorically elicited form of negativism (akin to the descriptive overlap of rigidity and negativism in the DSM-IV and IV-TR, see Table 1 footnote) but also describe a “social and interpersonal” negativism evidenced by the patient’s negativistic response to others, rules, or social convention. Northoff features a similar item autism/withdrawal (N.B11), although its central theme is “social” withdrawal, either passively or actively. Regarding negativism, the idea of “doing the opposite” of a request is described in the ICD (“contrary”), Northoff (N.B10), Bush-Francis (BF12), Bräunig (B19), Rosebush and Fink-Taylor; however, the DSM uses only the word “opposition,” whose literal reading would be opposing, not doing the opposite. As for thresholds, Northoff requires that the finding be exhibited at least 5 times; Bräunig specifies 5, 15, and 30 min as cutoffs for grading severity.

Per ICD, staring includes a fixed gaze and decreased blinking, which is often expressed with “widely opened eyes.” The DSM does not contain staring a diagnostic criterion. Both Northoff (N.A11) and Bush-Francis (BF4) include staring with wording roughly equivalent to ICD, but Rosebush describes staring only as “decreased frequency of blinking.” Northoff is unique in adding the comment that staring is “often accompanied by subjective experience of extreme and uncontrollable emotional states.” Additionally, Northoff specifies a threshold of 20 sec before scoring this item.

Ambitendency is included in ICD, Bush-Francis (BF19), Northoff (N.A10, “ambivalency”), and Fink-Taylor. Per ICD, it is described as “being ‘motorically stuck’ in indecisive or hesitant movement,” which is nearly verbatim with Bush-Francis and Fink-Taylor. Northoff takes a uniquely psychological approach to this item as reflected in its use of the term ambivalency, which describes an emotional balance rather than the externally visible behavioral phenomenon of ambitendency. Northoff describes ambivalency as the underlying “conflicting (and/or opposing) emotions (and/or thoughts),” which then manifests itself as appearing “blocked (‘stuck’), indecisive, and hesitant” behaviorally.

Two additional features of decreased activity are described by Northoff: flat affect (N.A7), which describes a state of emotional blunting, and affective latency (N.A8), in which emotional responses are abnormally delayed.

2.3. Increased psychomotor activity

ICD and DSM take substantively different approaches to the criteria of increased activity. DSM includes a single item of increased psychomotor activity among its diagnostic criteria. ICD, on the other hand, lists from 3 to 5 items (depending on how one reads the conjunctions) of increased activity but notes that any combination of these findings “should be counted as only one of the three required symptoms” for catatonia diagnosis.

The single item in DSM is agitation, but a definition is not provided. The parenthetical comment clarifies only that this finding not be a response to environmental stimuli. ICD includes agitation in the phrase “extreme hyperactivity or agitation for no reason with nonpurposeful movements and/or uncontrollable, extreme emotional reactions.” The two instances of the word “or” render this phrase, all listed on the same line, ambiguous. Taken literally, this would include three separate features, though the similarity of wording to two items on Northoff’s scale would suggest that this was intended as an abridgement of Northoff’s excitement and agitation (see next paragraph).

Bush-Francis and Bräunig each include a single item of increased activity, excitement (BF1 and B10), which do not reference associated emotional states. Rogers includes two separate items of overactivity, though these are differentiated based on whether the finding was directly observed by the clinician (R18) or reported by collateral (R21). In all three of these scales, akathisia is explicitly excluded. The two Northoff items that parallel the ICD definition are excitement (N.A5, “extreme hyperactivity with nonpurposeful movements and extreme emotional reactions”) and agitation (N.A12 “inner…and/or outer…restlessness in relation to intense emotional experiences”). Even on a close reading of these two findings, however, one finds substantial overlap in that a person with “outer restlessness” (per agitation) would also score positive for excitement. In addition to these two findings of increased activity by Northoff are four emotion-focused items that might be considered under the “uncontrollable, extreme emotional reactions” described by ICD. These include affect-related behavior (N.A6, abnormal movements and behaviors attributed to emotional states), compulsive emotions (N.A1, abnormal, involuntary affective reactions), emotional lability (N.A2, as traditionally understood), and anxiety (N.A9, affective, verbal, and/or autonomic signs of intense anxiety). Rosebush does not include an item describing a generalized increase in motor activity. Fink and Taylor describe excitement not as a specific symptom but as a syndromal presentation that can include incessant talking, impulsive, stereotypy, denudative behavior, and the potential for violence. Thresholds are not provided for any item above.

The next feature of increased activity in ICD is impulsivity, or sudden, inappropriate behavior without clear cause. This is nearly identical in definition to the Bush-Francis item of impulsivity (BF15). According to Northoff, impulsivity (N.A3) is understood rather as the underlying “emotional reaction,” which then manifests outwardly as “inadequate behavior.” Bräunig includes in its definition of this item (B20, “impulsiveness”) not only sudden, inappropriate behavior but also aggression directed at oneself or others. Aggression would be scored separately in ICD, Bush-Francis and Northoff (see following paragraph). Only Bräunig specifies cutoffs: 5, 15, and 30 min.

The final item of increased activity included in ICD is combativeness, which is physical aggression or “striking out” against others. This is nearly equivalent to the item of combativeness on Bush-Francis (BF22). The analogous item on Northoff (N.A4, “aggression”) is described as “verbal or violent attacks” and, as with other items of increased activity, linked with “extreme emotional states.” As above, aggression is scored as impulsiveness per Bräunig.

Automatic obedience is included by Bush-Francis (BF16), Northoff (N.B6), and Bräunig (B18, “automatic”) but is absent in ICD and DSM. In each, the person exhibits “exaggerated cooperation” or “compliance, obedience, suggestibility, and tendency to affirm.” This finding has occasionally been called “positivism” (e.g., Lohr-Wisniewski) as it represents the inverse expression of negativism or as “command automatism” (e.g., Barnes). Both Bush-Francis (i.e., in the Training Manual) and Northoff note that such obedience includes cooperating with requests that are senseless or even potentially dangerous. Although Fink and Taylor use this term, they describe it as the finding of mitgehen (i.e., like an anglepoise lamp) as elicited in the Bush-Francis or Rogers. Northoff specifies that this finding be exhibited more than five times before scoring, and Bräunig includes the cutoffs of 5, 15, and 30 min for grading severity.

2.4. Autonomic abnormality

When pronounced autonomic abnormality occurs in catatonia, the condition is called “malignant catatonia,” and it represents a life-threatening emergency. It is included in ICD as a specifier, but this critical sign is not included in DSM. Bush-Francis lists temperature, blood pressure, pulse, respiratory rate, and diaphoresis as potential parameters of autonomic abnormality (BF23). In Northoff, the item “vegetative abnormalities” (N.B15) includes “subjective (i.e., sweating, perspiration, palpitations, and so forth) and objective (i.e., temperature, pulse, blood pressure, respiratory rate, and so forth) signs.” It is unclear why two synonyms—sweating and perspiration—are both used or why these are included under subjective as they can be objectively observed and evaluated. Additionally, the inclusion of “so forth” is unique in this context as it leaves open the question of what other items might be included, perhaps introducing a source for additional variance. Although not included as a diagnostic feature per Fink-Taylor, autonomic abnormality is discussed in detail in their chapter on malignant catatonia.

3. Discussion

Despite the increasing harmonization of catatonia’s features between the ICD and DSM, several notable limitations have been identified including the lack of thresholds for individual items in both systems and the lack of autonomic abnormality in DSM (Table 4). There are also many significant distinctions across rating scales that will lead to discrepant classification of specific items, and many rating scale items will need to be modified to be faithfully converted to diagnostic criteria. To enhance reliability, future studies would do well to report how each of the items have been scored. Notable examples include waxy flexibility and rigidity on Bush-Francis, the uniquely restrictive definition of mutism on Northoff, and the symptom-complex motor and muscle tone items of posturing, waxy flexibility, and posturing on Bräunig. Moreover, several items on standard diagnostic criteria are not included on Bräunig or Rogers, rendering them inadequate.

Table 4:

Summary of key distinctions across diagnostic criteria and rating scales

	Core elements of consensus definitions in ICD and DSM	Notable distinctions across rating scales	Limitations in definitions in addition to lack of thresholds
Abnormal psychomotor activity
Posturing	• Posture maintained against gravity • Assumed spontaneously	• Bräunig’s description of these as symptom clusters is an outlier and not easily converted to diagnostic criteria. • The Bush-Francis definition of waxy flexibility as initial resistance before allowing reposturing does not convert to diagnostic criteria. • Bush-Francis excludes cogwheel rigidity as “rigidity,” but Northoff includes it.	• If one does not observe the beginning of the movement, it may be impossible to ascertain posturing as opposed to catalepsy. The distinction between these items is of unclear phenotypic value.
Catalepsy	• Posture maintained against gravity • Induced passively • Requires physical examination
Waxy flexibility	• Slight, even resistance to passive range of motion • Requires physical examination		• Criterion overlap between waxy flexibility and rigidity on ICD-11. As currently defined, waxy flexibility qualifies as a mild form of rigidity.
Rigidity	• Resistance to passive range of motion • Requires physical examination
Mannerism	• Odd character of movements • Movements are purposeful	• Manneristic speech qualifies as mannerism on Bush-Francis. It is a separate item on Northoff and Rogers.	• Manneristic speech not included in definition.
Stereotypy	• Repeated, non-purposeful movements • Abnormality in frequency of movement		• Stereotypic speech patterns qualify as verbigeration, but this distinction is of unclear phenotypic value.
Grimacing	• Odd or distorted facial expressions	• Rogers differentiates grimacing from mannerisms or stereotypies of the face and head. • Fink and Taylor describe grimacing as “facial posturing.”	• It is unclear whether grimacing includes only fixed expressions or also includes facial mannerism and stereotypy. • The value of distinguishing facial findings from findings in other body regions is of unclear phenotypic value.
Echophenomena	• Spontaneous mimicry of speech (echolalia) or movements (echopraxia)	• Fink and Taylor specify that echophenomena persist despite instructions to the contrary.	• DSM differs from ICD by allowing mimicry of persons other than the examiner to qualify.
Verbigeration	• Repetition of words, phrases, or sentences	• Unit of repetition varies across scales.	• As above, the value of differentiating verbigeration from stereotypy is unclear.
Decreased psychomotor activity
Stupor	• No or markedly reduced activity • Minimal responsiveness to external stimuli	• Northoff and Rogers each include three items loosely related to stupor.	• DSM’s requirement of “no” psychomotor activity for stupor is unusually restrictive.
Mutism	• No or very little verbal response	• Bush-Francis and Bräunig include “incomprehensible whispers” as mutism. Northoff restricts mutism to “no verbal responses.”	• Whether “incomprehensible whispers” qualifies as mutism according to DSM and ICD is unclear.
Negativism	• Opposition or non-response to instructions or external stimuli	• Bush-Francis Training Manual clarifies that failing to stop a behavior scored as a separate finding should not also be scored as negativism. • ICD includes withdrawal as negativism; Bush-Francis and Northoff include withdrawal as a separate item. • Bush-Francis includes avoidance of eye contact as evidence of withdrawal.	• DSM does not specify whether doing the opposite of instructions qualifies. • Clarification to exclude the potential double-scoring of negativism should be considered.
Withdrawal	• Withdrawal from social interactions • Refusal to take food or drink		• Given the importance of nutrition and hydration, the lack of a threshold for this feature deserves careful attention.
Staring	• Fixed gaze or decreased blinking	• Northoff describes commonly associated emotional states.
Ambitendency	• Being motorically stuck in indecisive or hesitant movement	• Northoff includes the related ambivalency, which describes the underlying emotional experience of ambitendency.	• ICD does not describe whether this is a spontaneous finding, elicited, or either.
Increased psychomotor activity
Agitation	• Markedly increased motor activity • Non-purposeful activity • No clear environmental cause ICD adds “uncontrollable, extreme emotional states”	• Northoff includes 2 items for motoric activity and 4 related items that describe extreme emotional states.	• DSM does not operationalize this feature. • The role of emotional states in agitation are emphasized by Northoff and ICD.
Impulsivity	• Sudden inappropriate behavior • No clear cause of behavior	• Northoff defines the underlying emotional reaction that is presenting behaviorally as impulsivity. • Bräunig includes combativeness as a type of impulsivity.
Combativeness	• Physical aggression toward others • “Usually” undirected	• Northoff includes verbal or violent attacks, which can be on “objects or other persons.”	• Although not a limitation per se, the phrase “usually in an undirected manner” is superfluous.
Autonomic abnormality
Autonomic abnormality (ICD specifier)	• Vital sign abnormalities “not fully accounted for by a comorbid medical condition” • Includes high or low heart rate, blood pressure, body temperature	• Bush-Francis and Northoff include diaphoresis as a feature.	• DSM does not include autonomic abnormality as a specifier.

ICD includes autonomic abnormality as a specifier; however, DSM has no corresponding item. With the field’s broad recognition of the importance of malignant catatonia, one sees a very strong argument for including autonomic abnormality as a specifier indicating clinical severity in subsequent editions of DSM. Malignant catatonia is the most severe form of catatonia and is associated with substantial morbidity including irreversible complications and death (Fink and Taylor, 2006). Future editions of the DSM would do well consider the relative merits of its inclusion in view of its clinical import and treatment implications.

The area of greatest disagreement across diagnostic criteria and rating scales concerns the motor findings of catatonia. A key historical reason for this confusion is the presence of contrasting historical traditions: one that sought to identify individual symptoms and another that merged these into symptom complexes. For instance, waxy flexibility is described as a symptom complex in the DSM-III: passive movement of a person’s limbs feels to the examiner as if they were made of pliable wax and the limbs can be “molded” into different positions that are subsequently maintained. DSM-IV then defined catalepsy and waxy flexibility synonymously (and, inexplicably, the same as posturing), yet modern ICD and DSM definitions separate catalepsy (induced postures) and waxy flexibility (slight, even resistance) as discrete signs. Current catatonia scales tend to separate these findings, though with differences across them, except for Bräunig, which takes a syndromal approach to not only waxy flexibility but also to posturing and rigidity. The fact that nearly all other signs of catatonia are identified individually suggests that this should be the preferred approach to motor findings as well. Additionally, one wonders whether waxy flexibility would be better subsumed under rigidity as a gradient of resistance to passive movement ranging from slight/mild (waxy flexibility) to severe (lead pipe rigidity) rigidity.

The primary distinction between core diagnostic criteria on ICD and DSM is their handling of increased activity. DSM includes a single item, agitation, whereas ICD includes 3 to 5 items depending on how one parses the first line. Such a distinction may be moot given that impulsivity and combativeness will all but invariably present with generally increased motor activity and thus be scorable as agitation per DSM. A simple way to address this would be for future editions of the DSM to offer a parenthetical comment defining the scope of agitation as it does with most other catatonia criteria. From a different perspective, the inclusion of several expressions of increased activity in ICD raises the question of whether increased activity properly deserves more than one independent feature in the DSM. That is, the distribution of diagnostic criteria currently favors catatonic syndromes characterized by decreased or abnormal psychomotor activity. As one final point of distinction, substance-induced catatonia would be diagnosed as unspecified catatonia in DSM whereas it is diagnosed separately as substance-induced catatonia in ICD.

Bush-Francis and Northoff are best positioned for conversion to clinical diagnostic criteria with only slight modification required—for example, see (Wilson et al., 2017)—and are the two scales most likely to be used for identifying catatonia. Bush-Francis is the most widely cited paper in the entire catatonia literature (Weleff et al., 2022), and only the Bush-Francis describes a semi-structured interview for detailed assessment as described in the initial publication (Bush et al., 1996) and elaborated in the Training Manual (Wortzel and Oldham, 2022). The Training Manual also provides detailed descriptions of each item and how to differentiate these from similar findings. Additionally, a suite of free instructional videos that provide detailed explanations of each item along with videographic case examples is available for Bush-Francis (Wortzel and Oldham, 2022). As an educational module, these resources have been demonstrated to improve accuracy of scoring across training levels (Wortzel et al., 2022). The clinical utility of Bush-Francis is also a strength in that all 12 core criteria in the DSM are included among its first 14 items, which comprise a stand-alone screening instrument.

Northoff includes the largest number of individual catatonia findings; it also uniquely emphasizes the affective and volitional domains of the catatonia phenotype. Anxiety and fear are common emotional experiences of persons with catatonia, and their presence has been associated with lorazepam response (Moskowitz, 2004). Also, drawing from Northoff, ICD-11 introduced emotional disturbance to its diagnostic criteria by adding the phrase “uncontrollable, extreme emotional reactions” to its description of agitation. However, whereas agitation often presents with clinically apparent emotional dysregulation (regardless of whether it occurs in catatonia or in other states), assessment of emotion or volition can often be challenging if not impossible in catatonia because the person is seldom at liberty to express themselves cogently with words. Determinations of voluntariness or controllability are also very difficult to standardize given the subjectivity inherent in intuiting volition (see motor features N.M3, N.M5, N.M6, N.M7, N.M9; affective features N.A1, N.A5, N.A9, N.A11; and behavior features N.B4, N.B6, N.B9).

4. Conclusions

Whereas the ICD and DSM broadly agree on their definitions of individual diagnostic criteria for catatonia and both require at least 3 items for diagnosis, there are nevertheless important distinctions between them. Compared with the DSM, ICD includes additional items, includes autonomic abnormality as a specifier, places a heavier focus on hyperkinetic catatonia than DSM, and offers a separate diagnosis for substance-induced catatonia. Importantly, neither system includes thresholds for identifying individual catatonia features. This survey of rating scales revealed many substantive discrepancies across criteria and scales including which items are included, how they are defined, and thresholds of what qualifies for a given item. As such, converting the results of clinically validated catatonia rating scales to either diagnostic system will require thoughtful modification. Of the available scales, Bush-Francis is the most clinically efficient, with comprehensive videographic resources available, whereas Northoff offers the most detailed clinical assessment, with a unique emphasis on the psychological aspect of this condition. Ultimately, whereas the differences across scales and criteria are many, the increasing harmonization of items and the rising visibility of this often marginalized syndrome are encouraging. It is hoped that this conceptual review clarifies important distinctions so that further advances can be made in refining and unifying the field’s understanding of catatonia.

Table 5:

Considerations regarding the catatonia phenotype

• Future research should report how individual items have been defined, including thresholds.  • Autonomic abnormality deserves inclusion as a specifier in subsequent editions of the DSM.  • A time period (e.g., 24-hours) should be defined for diagnosing catatonia.  • Further investigation should consider the relative merits of prioritizing or requiring certain features for diagnosis, which might aid in reliable detection.  • The indexical nature of DSM and ICD (i.e., as opposed to being constitutive) means that further consideration should be given to abridging the list of features for clinical utility.  • The effect of further balancing the relative proportion of hypokinetic, hyperkinetic, and parakinetic findings among diagnostic criteria deserves exploration.  • The roles of emotion and volition in detecting, diagnosing, and characterizing catatonia remains a topic for investigation.