Originally considered by Kahlbaum to be an independent disease entity characterized by mental and motor abnormalities, catatonia was later viewed as a subtype of schizophrenia as it is the case in current classifications like ICD-10 and DSM-IV. Since catatonic symptoms were observable not only in schizophrenic psychoses, but also in affective, somatic or even psychogenic disorders, many researchers today consider catatonia as a nosologically unspecific syndrome. In the end, the traditional conceptions did not succeed in defining catatonia as a clinically homogeneous and valid diagnosis.

An independent conception of catatonia was elaborated by the Wernicke-Kleist-Leonhard school of psychiatry. Based on a precise differentiation of diagnostically specific qualitative psychomotor disturbances, two essentially distinct forms of catatonic psychoses have been separated which differ in symptomatology, prognosis and treatment: on the one hand periodic catatonia, and on the other hand the group of systematic catatonias.

Periodic catatonia usually has an acute onset, shows a bipolar and polymorphous symptomatology and runs an intermittent course. After one or more acute attacks, adynamic residual states of varying degrees of severity develop. Hyperkinetic and akinetic distortions of psychomotor activity are characteristically intermingled in attacks and residual states.

In contrast, systematic catatonias begin insidiously, run a chronically progredient course without remissions and develop clear-cut and stable residual states. Six subtypes can be distinguished, each of which is characterized by a specific symptom constellation.