No Effect of the 1918 Influenza Pandemic on the Incidence of Acute Compulsory Psychiatric Admissions in Amsterdam

Abstract

Influenza pandemics are a recurrent phenomenon with a considerable impact on public health. Little is known however of their influence on mental health. Influenza A viruses are neurovirulent; during the pandemic of 1918 for instance, neurological complications were observed ranging from single neuropathies to encephalitis lethargica. Another complication was acute psychosis, which could occur in hitherto men tally healthy individuals until shortly after the symp toms of infection had subsided and which was hard to distinguish from schizophrenia (Menninger [1]). A new influenza pandemic causing this kind of mor bidity could affect facilities for acute psychiatric admis sions that often already are strained to their limits. We studied the impact of the 1918 influenza pandemic in Amsterdam on the number of acute psychiatric admis sionsinthatperiodbycomparingmortalitydatawithdata from the registry for acute compulsory psychiatric admissionsoftheMunicipalHealthAuthority. Only data on mortality due to influenza proper were used (Quanjer [2]); as fatalities due to the viral i fecti itself usually occurred within a week after the fir t symptoms, these numbers were considered to be a reason ble measure for the timeframe within which the m rbidity reached pandemic levels. Acute compulsory admissions were well docu mented b cause of their judicial consequences; regis trations included an abstract of the psychiatric examination; they were tallied by hand by one of the authors. At face value the same type of patient was admitted as nowadays in Amsterdam. Admission facilities were just as constrained. The registry reflects the incidence of psychotic complications as the typi al agit tion and loss of impulse control would necessitate psychiatric commitment, which was usu ally i voluntary; in the Netherlands, open wards for voluntary placement in psychiatric hospitals only started to be developed after 1915. The results are presented in Figure 1 and Table 1. In October and November the pandemic passed through Amsterdam and most of the mortality occurred. The admission numbers during this period were slightly