Catatonia: "Fluctuat nec mergitur".

In the beginning of the 1900s, the prevalence of catatonia in inpatient samples was reported to be between 19.5% and 50%. From the mid-1900s, most clinicians thought that catatonia was disappearing. Advances in medical sciences, particularly in the field of neurology, may have reduced the incidence of neurological diseases that present with catatonic features or mitigated their severity. More active pharmacological and psychosocial treatment methods may have either eliminated or moderated catatonic phenomena. Moreover, the relatively narrow descriptive features in modern classifications compared with classical texts and ascribing catatonic signs and symptoms to antipsychotic-induced motor symptoms may have contributed to an apparent decline in the incidence of catatonia. The application of catatonia rating scales introduced in the 1990s revealed significantly more symptoms than routine clinical interviews, and within a few years, the notion of the disappearance of catatonia gave way to its un-expected resurgence. Several systematic investigations have found that, on average, 10% of acute psychotic patients present with catatonic features. In this editorial, the changes in the incidence of catatonia and the possible underlying causes are reviewed.