Catatonia, schizophrenia, and affective disorders - Diagnostic associations in different cultural settings.

The nosological status of catatonia in modern classificatory systems and the influence of culture on its presentation are not fully understood. A secondary analysis of the data collected for another study that looked at the incidence of catatonia in India and Wales was performed to examine the association of catatonia to ICD 10 F diagnostic categories in two different cultural settings. The most common clinical diagnosis assigned by clinicians in India was from ICD10 F 20, while in Wales it was from ICD10 F30. The differences between the two settings were found in the F20 group. Association of catatonia appears to be more consistent with affective disorders in the two settings, but not with schizophrenia spectrum disorders. The findings are subjected to the limitations of secondary analysis.

INTRODUCTION

Catatonia was re-defined as a neuropsychiatric syndrome in the twentieth century.[12]Catatonia is known to occur in association with several mental disorders.[3] However, the understanding of the nosological status of catatonia in the current classificatory systems is not satisfactory.[4-6] Studied using standardized instruments,[78] catatonia was reported to be common in different cultures.[9-11] While the association of catatonia was reported to be stronger with affective disorders in western settings,[12] reports from different countries indicated that catatonia may be more closely related to schizophrenia spectrum disorders[111314] with the implication that culture and ethnicity may influence how catatonia manifests in relation to different psychiatric disorders.

OBJECTIVE

To examine the relationship of catatonia with the diagnostic categories in the mental and behavioral disorders section of the International Classification of Diseases (ICD 10 F)[15] by performing secondary analysis of the data that was collected from two psychiatric admission units when studying the incidence of catatonia as a neuropsychiatric syndrome in two cultural settings.[10]

MATERIALS AND METHODS

While the reader may find the full methodological details in the report of the primary study,[10] a brief account of the methods used is given herewith.

A predetermined number of 104 consecutively admitted patients to the Institute of Mental Health (IMH) in India and patients admitted to Hergest Unit (HU) in Wales were systematically screened for catatonic features using the Bush Francis Catatonia Screening Instrument and Rating Scale (BFCSI and BFCRS).[78]

The BFCRS is an instrument that was developed to facilitate the systematic examination of catatonic signs based on the operationalized definitions of signs ascribed to catatonia in published sources and reported to have good validity and interrater reliability. The instrument has since been widely used in several cultural settings worldwide.[9-11]

The BFCRS itself has 23 items, with the first 14 items truncated to form the BFCSI, with an operational criterion of two or more features on BFCSI, to be present and persist for at least 48 hours to be able to diagnose catatonia. The standardized examination procedure that was recommended to be applied when using the instrument made it easy to apply it in varied settings.

The researcher (PC), who had no role in patient management decisions and no control over what diagnoses the patients would receive, had screened all the patients for catatonia following the recommended procedure and simultaneously collected the required data on the demographics of the patients screened for catatonia. Catatonia was diagnosed as per the criteria recommended by Bush et al., irrespective of the clinical diagnosis assigned by the treating physicians. After the screening procedure for catatonia was completed the data on ICD-10 diagnoses, as assigned by the treating team as part of their routine clinical practice, was collected from the records.

A specific feature of the study design that is relevant to this particular analysis is that the psychiatrists who had clinical responsibility for the patients and had assigned the ICD10 F diagnoses as part of their regular clinical practice in real life situations, in both the settings, were neither involved in diagnosing catatonia nor were they made aware of the status of catatonia that was rated by the researcher (PC). At the same time the researcher had made no attempt at making the ICD10 diagnosis, nor did (s)he have the knowledge of what diagnosis the clinicians may have assigned to any particular patient, while screening the patients for catatonia. Hence, the researcher was not influenced by the possible clinical diagnosis the patient may have been assigned when rating the catatonic features, and the clinicians were not influenced by the ratings related to catatonia while assigning the ICD 10 diagnoses.

The ICD 10F diagnostic categories received by all the patients in the two settings were tested for differences in proportions of the cases and non-cases of catatonia. Although catatonia was found in association with a range of mental disorders, in view of the small numbers (or none in some groups) in other diagnostic categories [Table 1], the statistical comparisons of the proportions of cases and non-cases of catatonia in both the settings was limited to the two main diagnostic groups of ICD10 F20 and ICD10 F30, with which catatonia is most commonly associated and discussed in literature.

Table 1

Demographic features and distribution of cases and non-cases of Catatonia in the two units in Wales and India in relation to various diagnostic categories of ICD 10 F

SPSSv17 was used to perform univariate and bivariate statistics, to describe and compare the demographic features of the two samples. The ‘Vassarstats’ computational website[16] was used specifically to run the Z ratios, to be able to compare the differences in proportions of cases and non-cases of catatonia in ICD10 F20 and F30 categories in the two settings. While doing so, the figures in each cell were inflated by multiplying them with a fixed factor of ten to be able to achieve the stipulated minimum numbers in each cell.[16]

RESULTS

The principle finding of the primary study was that the frequency of catatonia as a non-specific neuropsychiatric syndrome was not significantly different in both settings, with 14 HU in Wales and 16 in IMH, in India, meeting the diagnosis of catatonia that are hitherto are referred as ‘cases’. The cases and non-cases of catatonia in India were younger with a shorter psychiatric history and a male predominance compared to Wales [Table 1].

Catatonia cases were found across ICD-10 F diagnostic categories pertaining to adult mental and behavioral disorders (ICD 10 F 00 to F60) in both the settings. The most common diagnosis assigned for both cases and non-cases of catatonia by the clinicians in India was for those from the group of schizophrenia and schizotypal and delusional disorders {54.81% (CI 0.45 to 0.65)}, whereas, in Wales it was from the affective disorder group {26.92% (CI 0.19 to 0.37)}.

Current analysis [Table 1] reveals that the proportions of cases and non-cases in both schizophrenia and affective disorder groups in HU are significantly different with six cases (42.86%), and 47 (51.11%) non-cases of catatonia received diagnoses other than the ICD 10 F20 and F30 categories. No such differences were found in IMH between the two categories, with only two (12.5%) cases and 18 (20.45%) non-cases receiving a diagnosis outside the F20 and F30 categories. Further comparisons for differences of proportions between the ratio of cases to non-cases, who received a diagnosis from the F20 category in HU (1/23) and IMH (10/47), revealed a significant difference in the Z ratio (two-tailed), of 5.78 (P<0.0002). However, when similar comparisons were made between the ratio of the cases received with a diagnosis from F30, HU (7/21) to those in IMH (4/23), the difference was less prominent, with a Z ratio (two-tailed), of 2.985 (p0.0028), indicating that the association of catatonia to affective disorders was fairly consistent in the two settings, but not in schizophrenia spectrum disorders.

DISCUSSION

The principle finding that emerged from this analysis is that the association of catatonia is more consistent with affective disorders in the two settings and not with schizophrenia spectrum disorders. The differences found in the proportions of cases and non-cases of catatonia in the F20 category in HU compared to that in IMH, may be explained by the differences in patient characteristics and admission practices in the two settings. However, considering that the ratios of the catatonia cases to non-cases of catatonia in the F20 spectrum disorders in IMH and HU are significantly different, it is difficult to attribute the differences in the frequency of F20 diagnoses in relation to catatonia cases solely to the demographic features of the local populations, such as, more number of younger male patients in the Indian setting. This finding that the most common diagnosis in the Indian setting for both cases and non-cases (more so with cases) of catatonia was from F20 category, is in keeping with the more recent reports, that examined the diagnostic associations and culture and ethnicity influence on the presentation of catatonia among non-white populations,[111314] and further supports the possibility of the pathoplastic influence of ethnicity and culture on the presentation of catatonia.

The observation that catatonia has occurred in association with a range of ICD 10 diagnostic categories and its fairly consistent association with affective disorders in both the settings, also supports the established view that catatonia has a stronger association with mood disorders.[12]

In spite of being a secondary analysis, there are certain strengths in the methods used. To begin with, the process of diagnosing catatonia was robust, with the catatonic features elicited systematically, using a standardized rating instrument, by a researcher not directly involved in the clinical care. Also the ICD 10F diagnoses were given by fully qualified psychiatrists treating the patients in real life situations, without being influenced by the status of catatonia, as elicited by the researcher. In addition, unlike other studies[1113] that examined the presentation and associations of catatonia to different diagnostic categories in any one setting, in this study this association of catatonia to ICD10 F diagnostic categories was examined in two diverse cultural settings, without influencing the local practises and vice versa. The findings from this analysis, however, are limited by the nature of the data that was primarily collected for another study, with different objectives, and having only small numbers in any given category. The numbers, however, are still comparable to those reported in recent studies[1113] on the subject.