Incidence Rates Of Schizophrenia Research Articles

Symptom Assessment in Casenotes and the Clinical Diagnosis of Schizophrenia

It is well known from several international studies that the incidence rates for schizophrenia, based on first-admission samples, are low in Denmark, especially in females, compared with other countries. This might be due to special diagnostic traditions in Denmark. To analyze how Danish psychiatrists reach a diagnosis of schizophrenia, a stratified subsample of 122 cases out of all 1,259 patients, aged between 12 and 64 years, with a first hospital admission in 1976 under the diagnosis of schizophrenia, paranoid psychosis, acute reactive paranoid psychosis, or casus limitaris was selected. For this subsample, psychopathological symptoms, as documented in the clinical casenotes, were rated by PSE-9 symptom lists for subsequent CATEGO analysis. The core syndrome of schizophrenia, as defined by the CATEGO class S+, showed no association with the clinical schizophrenia diagnosis compared with the other diagnoses mentioned. Also, positive symptoms of schizophrenia did not determine the diagnosis, but for typical negative symptoms such associations were indicated. Some negative symptoms also seemed to be linked to a depressive state. Furthermore, the present work indicates that using first-admission data leads to a higher age at schizophrenia onset and a lower first-admission rate in Denmark compared with Germany.

Evidence for a Gender-Specific Decline in the Rate of Schizophrenia in Rural Ireland over a 50-Year Period

The issue of whether the incidence rate of schizophrenia may have declined over recent decades has generated considerable controversy. This study sought to ascertain and interview all patients who satisfied contemporary diagnostic criteria for schizophrenia within a defined and unusually homogeneous region of rural Ireland having a total population of 25,178 people; morbid risk for schizophrenia was then examined by quinquennia of birth from 1920-24 to 1965-69. Morbid risk appeared essentially constant for persons born between 1920 and 1939 but fell by 37% for those born between 1940 and 1969, the fall being considerably more prominent in females (-56%) than in males (-19%). Attention is focused on sexual dimorphism in cerebral development and on temporal changes in endogenous or exogenous factors that influence the rate of occurrence of schizophrenia in females.

Folnegović & Folnevogić-Šmalc's “Schizophrenia in Croatia: Inter-regional Differences in Prevalence and a Comment on Constant Incidence”

"STUDY OBJECTIVE--The aim was to examine why differences exist in schizophrenia prevalence and risk in some areas of Croatia, when schizophrenia incidence rates do not appear to vary. DESIGN--Areas differing by schizophrenia admission rates in patients born in 1953 and admitted by the age of 31 years are compared using a number of indicators relating both to general population characteristics and to those of schizophrenic cases in these populations. SETTING--The study covers the whole of Croatia (4,601,469 inhabitants, 1981 census). SUBJECTS--By the age of 31 years, out of 80,445 individuals born in Croatia in 1953, 464 were admitted for and diagnosed as having schizophrenia. MAIN RESULTS--Admission risk rates are higher in those parts of Croatia where emigration rates are high and lower where immigration rates are high. There is also a positive correlation with schizophrenia prevalence and manic depressive psychosis rates. There is a negative correlation with age of onset of schizophrenia and with schizophrenic reproduction rates. In the study areas, hospital incidence rates are not significantly different. CONCLUSIONS--Economic migration and negative selection in the domestic population are likely to be the most significant factors leading to differences in schizophrenia prevalence. The approximately equal incidence rates in the population, with different prevalence and admission risks, are linked to differences in the disease onset among schizophrenics with a positive family history for this condition. In other words, these patients, when part of the population with a greater prevalence and a greater hereditary loading, experience the onset more often at an earlier age. Thus they have a lower reproduction rate than in a population with a lower prevalence and a lower hereditary loading. Thus incidence rates in populations with different prevalences and different hereditary loads are maintained roughly equal over generations."

Invisible schizophrenia: A postal survey of the incidence and management of new cases of schizophrenia in primary care

Most new cases of schizophrenia are referred to hospital by general practitioners. It has been assumed that newly diagnosed schizophrenic patients pass through the filter between primary care and specialist psychiatric services with minimal delay. Little, however, is known of the incidence and initial management of schizophrenia in primary care. In this study questionnaires were sent to 175 general practitioners in Camberwell and Gloucester, enquiring after their experience of managing schizophrenia. Sixty per cent of respondents had seen an undiagnosed schizophrenic patient at some stage of their career. The general practice annual incidence rate of schizophrenia was estimated to be 12/100,000 in Gloucester and 26/100,000 in Camberwell. The large majority of patients were seen by a psychiatrist within a few weeks of general practitioner contact, but a significant minority of general practitioners sought to manage patients without making referral and prescribed psychotropic drugs before receiving an opinion. Eight per cent of patients did not see a psychiatrist.

Are incidence rates of schizophrenia decreasing?

An abstract is not available for this content so a preview has been provided. As you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Ecological structure and incidence rates of schizophrenia in Nagasaki City.

The purpose of this study was to investigate the relationship between incidence rates of schizophrenia and residential features in Nagasaki City, Japan. Social features of residents in 259 areas in the Nagasaki City ecological structure were determined using the results of the 1980 national census. Six residential factors--employment status, occupational and academic career, household status, length of residence, housing tenure and young male predominance--were selected as factors that clearly reflect residential differentiation of residents. Contrary to the findings of many other studies conducted in Western cities, no statistically significant differences were observed, although it seemed that incidence rates were comparatively higher in the lower social classes. These results possibly reflect differences in cultural and social values and structures.

Schizophrenia in Croatia: interregional differences in prevalence and a comment on constant incidence.

The aim was to examine why differences exist in schizophrenia prevalence and risk in some areas of Croatia, when schizophrenia incidence rates do not appear to vary. Areas differing by schizophrenia admission rates in patients born in 1953 and admitted by the age of 31 years are compared using a number of indicators relating both to general population characteristics and to those of schizophrenic cases in these populations. The study covers the whole of Croatia (4,601,469 inhabitants, 1981 census). By the age of 31 years, out of 80,445 individuals born in Croatia in 1953, 464 were admitted for and diagnosed as having schizophrenia. Admission risk rates are higher in those parts of Croatia where emigration rates are high and lower where immigration rates are high. There is also a positive correlation with schizophrenia prevalence and manic depressive psychosis rates. There is a negative correlation with age of onset of schizophrenia and with schizophrenic reproduction rates. In the study areas, hospital incidence rates are not significantly different. Economic migration and negative selection in the domestic population are likely to be the most significant factors leading to differences in schizophrenia prevalence. The approximately equal incidence rates in the population, with different prevalence and admission risks, are linked to differences in the disease onset among schizophrenics with a positive family history for this condition. In other words, these patients, when part of the population with a greater prevalence and a greater hereditary loading, experience the onset more often at an earlier age. Thus they have a lower reproduction rate than in a population with a lower prevalence and a lower hereditary loading. Thus incidence rates in populations with different prevalences and different hereditary loads are maintained roughly equal over generations.

Epidemiological studies of schizophrenia in Japan.

This article examines epidemiological studies of schizophrenia in Japan. It is divided into three major sections: (1) methodological problems associated with epidemiological studies; (2) an overview of the history of epidemiology in Japan; and (3) an epidemiological study on incidence rates in Nagasaki, which was conducted as part of the World Health Organization Collaborative Study on Determinants of Outcome of Severe Mental Disorders. In general, although some differences in schizophrenic subtypes have been found, prevalence and incidence rates of schizophrenia in Japan are not significantly different from those reported in other countries.

Characteristics of Male and Female Schizophrenics at First Admission

Based on information from a case register, patient age and diagnosis at first admission are analysed in a Croatian cohort of schizophrenics first admitted in 1972 and followed up through the register for 12 years. Diagnosis was analysed on the same basis and over the same period. Although the male and female differences in incidence rates for schizophrenia were not large, hospital incidence rates in younger age groups were higher in males. Males were also more commonly diagnosed as schizophrenic at first admission, females more frequently receiving diagnoses of affective psychosis and other organic psychosis, except for alcohol-induced psychosis.

The Incidence of Schizophrenia in Croatia

Hospital-based annual incidence rates for schizophrenia in Croatia over 1965-84 did not change significantly. Rates ranged from 0.21 to 0.22 per 1,000 population (0.26-0.29 per 1,000 population aged over 15). Factors that could influence these rates were analysed, but it appeared that the rates were a true reflection of the incidence rate of schizophrenia in the Croatian population.

ERRATUM

In our November, 1981, issue, in the article by Pulver et al., “The Association Between Season of Birth and the Risk for Schizophrenia” (Am J Epidemiol 1981;114:735–49), our printer inadvertently transposed the figures that appear on pages 738–9 (figures 1 and 2). The figure presented on page 738, now labeled as figure 1, should be figure 2, the hypothetical incidence curve for schizophrenia in Monroe County, New York, 1969–1971, while the figure now captioned as figure 2 on page 739 should be figure 1, the actual three-year age-specific incidence rates for schizophrenia in the county in 1969–1971. The Journal regrets this error.

A 5‐year retrospective investigation of all first admitted schizophrenics to Danish psychiatric institutions in the fiscal year from April 1st, 1970, to April 1st, 1971

A 5‐year retrospective study of 492 patients with a diagnosis of schizophrenia is reported. 81 % of the patients were discharged less than 6 months after their first admission, mostly to their homes. About 80% of the patients were admitted more than 1 time. After the first year, the readmission rate was about 15 % of all admissions. Thirty‐five per cent of the patients were committed one or more times to a mental hospital. The patient spent an average of 418 days in hospital. 9–60 % of the patients can be considered to be chronically ill, depending on the definition of chronicity. After 2 years in hospital, the chance of discharge was 15%. Suicide rate was 9 times higher in the patients than in the normal population. Sixty‐eight per cent of patients got a disability pension during the period of the study. The incidence rate of schizophrenia differed by a factor of 14 between capital‐city area and rural districts. The expectancy of schizophrenia was estimated to be between 0.34 % ‐ 0.67 %, depending on sex.

SOCIAL CLASS AND SCHIZOPHRENIA.

This study examines the relationship between the incidence of schizophrenia and social class in two culturally contrasting subcommunities in Detroit. The study focused on (1) whether the incidence rates of schizophrenia vary inversely with the class structure and (2) the relationship of incidence to vertical mobility. Results indicate that, although there is a heavy concentration of schizophrenics in the lowest social class, there are no significant differences in its incidence among the other four classes.