Abstract
Mendhekar et al. reported a patient with ‘recurrent seasonal confusional psychosis’ considered a case of cycloid psychosis [1], and Ferraro pointed out that they might have overlooked the presence of catatonia [2]. The occurrence of catatonia and its diagnostic significance in cycloid psychosis, an area marked by confusion and paucity of data, merits further discussion.
Cycloid psychosis, a term coined by Kleist and meticulously elaborated by Leonhard [3], has attracted considerable research interest but remains unfamiliar to many Australian psychiatrists. Although it has not found a place in the DSM system, ICD-10 maintains the concept of cycloid psychosis. Another term, ‘acute polymorphic psychotic disorder’ (F23.0, F23.1) is used for cycloid psychosis with an emphasis on the polymorphic syndrome – rapidly changing and variable psychotic symptoms and emotional states – as a cardinal feature.
Motility disturbance is a common feature in cycloid psychosis. Leonhard distinguished a motility subtype of cycloid psychosis characterized by hyperkinetic-akinetic disturbances, along with two other subtypes – the anxiety-happiness psychosis and confusional psychosis [3]. Perris, a strong proponent of cycloid psychosis, did not accept the subtyping and asserted that mixed forms were the rule rather than exception [4]. Both Leonhard and Perris attempted to differentiate the motility disturbances in cycloid psychosis from catatonic phenomena. According to Leonhard, the movements are only quantitatively different from normal in motility disturbances, whereas they are qualitatively different in catatonia [3]. Under the Leonhardian classification of endogenous psychoses, the presence of prominent catatonic features in an otherwise cycloid psychosis presentation (recurrent episodes with polymorphic symptoms) would shift the diagnosis to ‘periodic catatonia’ – an entity unfamiliar or unknown to most psychiatrists and a diagnosis to consider in Mendhekar et al.'s reported case.
It is, however, difficult to differentiate ‘cycloid’ psychomotor excitations and inhibition from catatonic excitement and stupor. Other catatonic symptoms, including mutism, posturing, catalepsy, grimacing, stereotypy, mannerism, rigidity, echolalia, verbigeration and negativism were frequently described in Leonhard's cases of cycloid psychosis. In his book Classification of endogenous psychoses, Leonhard remarked that ‘periodic catatonia is related to motility psychosis but goes considerably deeper’ and argued that the two can be differentiated in terms of their longitudinal course and heritability. Periodic catatonia, considered a type of schizophrenia, is characterized in its end state by residual symptoms and defects, which may be absent in some cases or not apparent at the early stage [3]. Although researchers in Würzburg have produced substantial data suggesting that periodic catatonia is a familial disorder with autosomal dominant inheritance [5], the nosological status of periodic catatonia as a homogeneous condition remains uncertain.
No data are available on the incidence of the catatonic syndrome in cycloid psychosis. Catatonia probably occurs frequently in cycloid psychosis. Its recognition has therapeutic and potentially prognostic significance. Catatonia merits treatment in its own right and its presence may affect the clinical course and prognosis of cycloid psychosis. It would appear clinically useful to distinguish a ‘catatonic subtype’ of cycloid psychosis, which resembles periodic catatonia – another condition of uncertain nosological status.