An epidemiological and clinical investigation of postpartum psychiatric illness in Japanese mothers

Abstract

A case note study of postpartum psychiatric illness as defined by Research Diagnostic Criteria (RDC) was conducted in an epidemiologically defined large area of Japan. The admission rate was 0.34/1000 live births. The most frequent diagnostic category was affective disorder (53%). “Atypical” symptoms were observed in 31% of all cases and were more frequent (67%) in patients with schizoaffective disorder. Fifty six percent of mothers developed a psychiatric illness within two weeks of delivery. The patients with “atypical” symptoms were admitted much more quickly and their length of stay in hospital was shorter.

Introduction

Estimates of the prevalence of psychosis after childbirth have usually been derived from studies of mothers admitted to psychiatric hospitals within a given period after delivery and such estimates typically range between 1–2/1000 deliveries (Brockington et al., 1982, Kumar, 1994). However, statistics derived from studies of complete populations of childbearing women suggest a generally higher rate – e.g. up to 4/1000 live births (Oates, 1996). The relative risk for the occurrence of psychotic breakdown is elevated at least 16 fold in the first month post-partum (Kendell et al., 1987) and for non-psychotic depressive disorder over the same time period there is about a doubling of risk (Cox et al., 1993). However, over longer periods, e.g. 3–12 months postnatally, the revalence of depression is similar to that in non-childbearing women (Cooper et al., 1988, O'Hara et al., 1990). There do not seem to be any major variations in the occurrence or manifestations of postpartum psychosis that are clearly related to ethnicity or culture (Polonio and Figueiredo, 1955, Swift, 1972, Cheetham et al., 1981, Murphy, 1982, Shoeb and Hassan, 1990). While it might be expected that cultural and social influences would play a major role in the causation and impact of non-psychotic depression following childbirth (see Stern and Kruckman, 1983) there is, so far, very little evidence for this (Kumar, 1994).

Recent studies (Brockington et al., 1981, Dean and Kendell, 1981, Katona, 1982, Klompenhouwer and Van Hulst, 1991) indicate that the majority of cases of severe postpartum psychiatric illness satisfy Research Diagnostic Criteria (RDC) (Spitzer et al., 1978) for bipolar-manic depressive, schizoaffective, or major depressive disorder. It has also been suggested that the symptomatology of postpartum psychiatric illness differs from that of non-puerperal cases (Brockington et al., 1981, Wisner et al., 1994) and that a distinctive cluster of symptoms exists in postpartum psychiatric illness primarily consisting of disturbances of awareness or consciousness in the absence of clear organic pathology – e.g. confusion, “incompetence”, perplexity, disorientation (Brockington et al., 1981, Dean and Kendell, 1981), or cognitive impairment (Wisner et al., 1994). The presence of such symptoms in the context of affective psychosis is regarded by some authorities as part of a diagnostic entity variously described as amentia (Pauleikhoff, 1964), cycloid psychosis (Perris, 1974), bouffée délirante (Ey, 1954) or atypical psychosis (Hatotani, 1996). However, operational diagnostic criteria such those in DSM-IV (APA, 1994) and ICD-10 (WHO, 1992) do not adequately cover the symptomatology of such fluctuations of consciousness and the nosological status of postpartum psychotic syndromes still remains controversial (McGörry et al., 1990, Brockington, 1996).

In order to examine differences in rates of illness and psychopathology between cultures, a necessary strategy is to use standardized methods of clinical assessments based upon operationalised clinical and diagnostic criteria, such as the RDC, and clearly defined time limits for the onset of illness. To our knowledge, there has been no large epidemiological survey of Japanese mothers based on all psychiatric admissions in a large area to verify whether or not there are similarities in rates of severe post-partum mental illness between Japan and other countries. The use of standardized “Western” methods and diagnostic classification systems carries with it the risk of missing symptoms or signs which may be evident in non-Western cultures and against which such methods may be insensitive. Japanese psychiatrists recognize the concept of “atypical psychosis” (Hatotani, 1996) and are therefore likely to record the presence of symptoms suggestive of cognitive impairment. Accordingly, a combined approach was adopted in this research; the Research Diagnostic Criteria were applied to the case notes of all childbearing women in Mie Prefecture who were admitted to psychiatric hospital up to 90 days postpartum. The RDC were supplemented by recording of “atypical” symptoms, i.e., fluctuation of consciousness in the absence of organic illness, consistent with the Japanese concept of atypical psychosis (Hatotani, 1996).